Reputation systems are programs or
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
s that allow users to rate each other in
online communities in order to build
trust
Trust often refers to:
* Trust (social science), confidence in or dependence on a person or quality
It may also refer to:
Business and law
* Trust law, a body of law under which one person holds property for the benefit of another
* Trust (bus ...
through
reputation. Some common uses of these systems can be found on
E-commerce
E-commerce (electronic commerce) is the activity of electronically buying or selling of products on online services or over the Internet. E-commerce draws on technologies such as mobile commerce, electronic funds transfer, supply chain manageme ...
websites such as
eBay
eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became a ...
,
Amazon.com
Amazon.com, Inc. ( ) is an American multinational technology company focusing on e-commerce, cloud computing, online advertising, digital streaming, and artificial intelligence. It has been referred to as "one of the most influential economi ...
, and
Etsy as well as online advice communities such as
Stack Exchange. These reputation systems represent a significant trend in "decision support for Internet mediated service provisions".
With the popularity of online communities for shopping, advice, and exchange of other important information, reputation systems are becoming vitally important to the online experience. The idea of reputation systems is that even if the consumer can't physically try a product or service, or see the person providing information, that they can be confident in the outcome of the exchange through trust built by
recommender systems.
Collaborative filtering, used most commonly in recommender systems, are related to reputation systems in that they both collect ratings from members of a community.
The core difference between reputation systems and collaborative filtering is the ways in which they use user feedback. In collaborative filtering, the goal is to find similarities between users in order to recommend products to customers. The role of reputation systems, in contrast, is to gather a collective opinion in order to build trust between users of an online community.
Types
Online
Howard Rheingold
Howard Rheingold (born 1947) is an American critic, writer, and teacher, known for his specialties on the cultural, social and political implications of modern communication media such as the Internet, mobile telephony and virtual communities (a t ...
states that online reputation systems are "computer-based technologies that make it possible to manipulate in new and powerful ways an old and essential human trait". Rheingold says that these systems arose as a result of the need for Internet users to gain trust in the individuals they transact with online. The trait he notes in human groups is that social functions such as gossip "keeps us up to date on who to trust, who other people trust, who is important, and who decides who is important". Internet sites such as
eBay
eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became a ...
and
Amazon
Amazon most often refers to:
* Amazons, a tribe of female warriors in Greek mythology
* Amazon rainforest, a rainforest covering most of the Amazon basin
* Amazon River, in South America
* Amazon (company), an American multinational technology c ...
, he argues, seek to make use of this social trait and are "built around the contributions of millions of customers, enhanced by reputation systems that police the quality of the content and transactions exchanged through the site".
Reputation banks
The emerging
sharing economy
In capitalism, the sharing economy is a socio-economic system built around the sharing of resources. It often involves a way of purchasing goods and services that differs from the traditional business model of companies hiring employees to produce ...
increases the importance of trust in
peer-to-peer
Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network. They are said to form a peer-to-peer n ...
marketplace
A marketplace or market place is a location where people regularly gather for the purchase and sale of provisions, livestock, and other goods. In different parts of the world, a marketplace may be described as a '' souk'' (from the Arabic), ' ...
s and services.
Users can build up reputation and trust in individual systems but usually don't have the ability to carry those reputations to other systems. Rachel Botsman and Roo Rogers argue in their book ''What's Mine is Yours'' (2010),
that "it is only a matter of time before there is some form of network that aggregates
reputation capital
Reputation capital is the quantitative measure of some entity's reputational value in some context – a community or marketplace. In the world of Web 2.0, what is increasingly valuable is trying to measure the effects of collaboration and con ...
across multiple forms of Collaborative Consumption". These systems, often referred to as reputation banks, try to give users a platform to manage their reputation capital across multiple systems.
Maintaining effective reputation systems
The main function of reputation systems is to build a sense of trust among users of online communities. As with
brick and mortar stores, trust and reputation can be built through
customer feedback
Customer service is the assistance and advice provided by a company to those people who buy or use its products or services. Each industry requires different levels of customer service, but in the end, the idea of a well-performed service is that ...
. Paul Resnick from the Association of Computing Machinery describes three properties that are necessary for reputation systems to operate effectively.
# Entities must have a long lifetime and create accurate expectations of future interactions.
# They must capture and distribute feedback about prior interactions.
# They must use feedback to guide trust.
These three properties are critically important in building reliable reputations, and all revolve around one important element: user feedback. User feedback in reputation systems, whether it be in the form of comments, ratings, or recommendations, is a valuable piece of information. Without user feedback, reputation systems cannot sustain an environment of trust.
Eliciting user feedback can have three related problems.
# The first of these problems is the willingness of users to provide feedback when the option to do so is not required. If an online community has a large stream of interactions happening, but no feedback is gathered, the environment of trust and reputation cannot be formed.
# The second of these problems is gaining negative feedback from users. Many factors contribute to users not wanting to give negative feedback, the most prominent being a fear of retaliation. When feedback is not anonymous, many users fear retaliation if negative feedback is given.
# The final problem related to user feedback is eliciting honest feedback from users. Although there is no concrete method for ensuring the truthfulness of feedback, if a community of honest feedback is established, new users will be more likely to give honest feedback as well.
Other pitfalls to effective reputation systems described by A. Josang et al. include change of identities and discrimination. Again these ideas tie back to the idea of regulating user actions in order to gain accurate and consistent user feedback. When analyzing different types of reputation systems it is important to look at these specific features in order to determine the effectiveness of each system.
Standardization attempt
The
IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...
proposed a protocol to exchange reputation data. It was originally aimed at email applications, but it was subsequently developed as a general architecture for a reputation-based service, followed by an email-specific part. However, the workhorse of email reputation remains with DNSxL's, which do not follow that protocol. Those specification don't say how to collect feedback —in fact, the ''granularity'' of email sending entities makes it impractical to collect feedback directly from recipients— but are only concerned with reputation query/response methods.
Notable examples of practical applications
* Search: web (see
PageRank)
* eCommerce:
eBay
eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became a ...
,
Epinions
Epinions.com was a general consumer review site established in 1999. Epinions was acquired in 2003 by DealTime, later Shopping.com, which was acquired by eBay in 2005. Epinions users could access reviews about a variety of items. On 25 March 2014 ...
,
Bizrate,
Trustpilot
* Social news:
Reddit
Reddit (; stylized in all lowercase as reddit) is an American social news aggregation, content rating, and discussion website. Registered users (commonly referred to as "Redditors") submit content to the site such as links, text posts, images ...
,
Digg
Digg, stylized in lowercase as digg, is an American news aggregator with a curated front page, aiming to select stories specifically for the Internet audience such as science, trending political issues, and viral Internet issues. It was launch ...
,
Imgur
* Programming communities:
Advogato
Advogato was an online community and social networking site dedicated to free software development and created by Raph Levien. In 2007, Steve Rainwater took over maintenance and new development from Raph. In 2016, Rainwater's running instance was ...
,
freelance marketplace
''Freelance'' (sometimes spelled ''free-lance'' or ''free lance''), ''freelancer'', or ''freelance worker'', are terms commonly used for a person who is self-employed and not necessarily committed to a particular employer long-term. Freelance w ...
s,
Stack Overflow
* Wikis: Increase contribution quantity and quality
* Internet Security:
TrustedSource
* Question-and-Answer sites:
Quora,
Yahoo! Answers
Yahoo! Answers was a community-driven question-and-answer (Q&A) website or knowledge market owned by Yahoo! where users would ask questions and answer those submitted by others, and upvote them to increase their visibility. Questions were orga ...
,
Gutefrage.net,
Stack Exchange
* Email:
DNSBL and
DNSWL provide global reputation about email senders
* Personal Reputation:
CouchSurfing (for travelers),
* Non Governmental organizations (NGOs): GreatNonProfits.org,
GlobalGiving
* Professional reputation of translators and translation outsourcers: BlueBoard at
ProZ.com
* All purpose reputation system:
Yelp, Inc.
Yelp Inc. is an American company that develops the Yelp.com website and the Yelp mobile app, which publish crowd-sourced reviews about businesses. It also operates Yelp Guest Manager, a table reservation service. It is headquartered in San F ...
* Academia: general
bibliometric
Bibliometrics is the use of statistical methods to analyse books, articles and other publications, especially in regard with scientific contents. Bibliometric methods are frequently used in the field of library and information science. Bibliom ...
measures, e.g. the
h-index
The ''h''-index is an author-level metric that measures both the productivity and citation impact of the publications, initially used for an individual scientist or scholar. The ''h''-index correlates with obvious success indicators such as winn ...
of a researcher.
Reputation as a resource
High
reputation capital
Reputation capital is the quantitative measure of some entity's reputational value in some context – a community or marketplace. In the world of Web 2.0, what is increasingly valuable is trying to measure the effects of collaboration and con ...
often confers benefits upon the holder. For example, a wide range of studies have found a positive correlation between seller rating and
asking price
Ask price, also called offer price, offer, asking price, or simply ask, is the price a seller states they will accept.
The seller may qualify the stated asking price as firm or negotiable. Firm means the seller is implying that the price is fixed ...
on
eBay
eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became a ...
, indicating that high reputation can help users obtain more money for their items. High
product reviews on online marketplaces can also help drive higher sales volumes.
Abstract reputation can be used as a kind of resource, to be traded away for short-term gains or built up by investing effort. For example, a company with a good reputation may sell lower-quality products for higher profit until their reputation falls, or they may sell higher-quality products to increase their reputation. Some reputation systems go further, making it explicitly possible to spend reputation within the system to derive a benefit. For example, on the
Stack Overflow community, reputation points can be spent on question "bounties" to incentivize other users to answer the question.
Even without an explicit spending mechanism in place, reputation systems often make it easier for users to spend their reputation without harming it excessively. For example, a
ridesharing company driver with a high ride acceptance score (a metric often used for driver reputation) may opt to be more selective about his or her clientele, decreasing the driver's acceptance score but improving his or her driving experience. With the explicit feedback provided by the service, drivers can carefully manage their selectivity to avoid being penalized too heavily.
Attacks and defense
Reputation systems are in general vulnerable to attacks, and many types of attacks are possible. As the reputation system tries to generate an accurate assessment based on various factors including but not limited to unpredictable user size and potential adversarial environments, the attacks and defense mechanisms play an important role in the reputation systems.
Attack classification of reputation system is based on identifying which system components and design choices are the targets of attacks. While the defense mechanisms are concluded based on existing reputation systems.
Attacker model
The capability of the attacker is determined by several characteristics, e.g., the location of the attacker related to the system (insider attacker vs. outsider attacker). An insider is an entity who has legitimate access to the system and can participate according to the system specifications, while an outsider is any unauthorized entity in the system who may or may not be identifiable.
As the outsider attack is much more similar to other attacks in a computer system environment, the insider attack gets more focus in the reputation system. Usually, there are some common assumptions: the attackers are motivated either by selfish or malicious intent and the attackers can either work alone or in coalitions.
Attack classification
Attacks against reputation systems are classified based on the goals and methods of the attacker.
* Self-promoting Attack. The attacker falsely increases their own reputation. A typical example is the so-called
Sybil attack where an attacker subverts the reputation system by creating a large number of
pseudonymous entities, and using them to gain a disproportionately large influence. A reputation system's vulnerability to a Sybil attack depends on how cheaply Sybils can be generated, the degree to which the reputation system accepts input from entities that do not have a chain of trust linking them to a trusted entity, and whether the reputation system treats all entities identically.
* Whitewashing Attack. The attacker uses some system vulnerability to update their reputation. This attack usually targets the reputation system’s formulation that is used to calculate the reputation result. The whitewashing attack can be combined with other types of attacks to make each one more effective.
* Slandering Attack. The attacker reports false data to lower the reputation of the victim nodes. It can be achieved by a single attacker or a coalition of attackers.
* Orchestrated Attack. The attacker orchestrates their efforts and employs several of the above strategies. One famous example of an orchestrated attack is known as an oscillation attack.
* Denial of Service Attack. The attacker prevents the calculation and dissemination of reputation values in reputation systems by using
Denial of Service method.
Defense strategies
Here are some strategies to prevent the above attacks.
* Preventing Multiple Identities
* Mitigating Generation of False Rumors
* Mitigating Spreading of False Rumors
* Preventing Short-Term Abuse of the System
* Mitigating Denial of Service Attacks
See also
*
Collaborative filtering
*
Collective influence algorithm
A collective is a group of entities that share or are motivated by at least one common issue or interest, or work together to achieve a common objective. Collectives can differ from cooperatives in that they are not necessarily focused upon an ...
*
Commons-based peer production
*
Defaulted executee
In China, judgment defaulter () or court defaulters, commonly known as laolai () or untrustworthy person (), is defined as a person who is able to fulfill legal obligations determined by the court, but has refused to do so, or illegally tries to e ...
*
Government by algorithm
*
Honor system
*
Influence-for-hire
*
Karma
Karma (; sa, कर्म}, ; pi, kamma, italic=yes) in Sanskrit means an action, work, or deed, and its effect or consequences. In Indian religions, the term more specifically refers to a principle of cause and effect, often descriptivel ...
*
Online participation
Online participation is used to describe the interaction between users and online communities on the web. Online communities often involve members to provide content to the website and/or contribute in some way. Examples of such include wikis, blog ...
*
Reputation capital
Reputation capital is the quantitative measure of some entity's reputational value in some context – a community or marketplace. In the world of Web 2.0, what is increasingly valuable is trying to measure the effects of collaboration and con ...
*
Reputation management
*
Sesame Credit
*
Social Credit System
The Social Credit System () is a national credit rating and blacklist being developed by the government of the People's Republic of China. The social credit initiative calls for the establishment of a record system so that businesses, indivi ...
*
Social currency
Social currency refers to the actual and potential resources from presence in social networks and communities, including both digital and offline. It is, in essence, an action made by a company or stance of being, to which consumers feel a sense ...
*
Sharing economy
In capitalism, the sharing economy is a socio-economic system built around the sharing of resources. It often involves a way of purchasing goods and services that differs from the traditional business model of companies hiring employees to produce ...
*
Social reputation in fiction
Social organisms, including human(s), live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary or not.
Etymology
The word "social" derives from ...
*
Social systems
*
Social translucence Social translucence (also referred as ''social awareness'') is a term that was proposed by Thomas Erickson and Wendy Kellogg to refer to "design digital systems that support coherent behavior by making participants and their activities visible to on ...
*
Subjective logic
*
Trust metric
In psychology and sociology, a trust metric is a measurement or metric of the degree to which one social actor (an individual or a group) trusts another social actor. Trust metrics may be abstracted in a manner that can be implemented on compute ...
*
Web of trust
*
Whuffie
''Down and Out in the Magic Kingdom'' is a 2003 science fiction book, the first novel by Canadian author and digital-rights activist Cory Doctorow. Concurrent with its publication by Tor Books, Doctorow released the entire text of the novel und ...
References
*
*
* D. Quercia, S. Hailes, L. Capra
Lightweight Distributed Trust Propagation ICDM 2007.
* R. Guha, R. Kumar, P. Raghavan, A. Tomkins
Propagation of Trust and Distrust WWW2004.
* A. Cheng, E. Friedman
Sybilproof reputation mechanisms SIGCOMM workshop on Economics of peer-to-peer systems, 2005.
* Hamed Alhoori, Omar Alvarez, Richard Furuta, Miguel Muñiz, Eduardo Urbina
Supporting the Creation of Scholarly Bibliographies by Communities through Online Reputation Based Social Collaboration.ECDL 2009: 180-191
Sybil Attacks Against Mobile Users: Friends and Foes to the Rescueby Daniele Quercia and Stephen Hailes. IEEE INFOCOM 2010.
* J.R. Douceur
The Sybil Attack. IPTPS02 2002.
*
*
*
* {{cite conference
, last1=Zhang , first1=Jie
, last2=Cohen , first2=Robin
, title=Trusting Advice from Other Buyers in E-Marketplaces: The Problem of Unfair Ratings
, conference=Proceedings of the Eighth International Conference on Electronic Commerce (ICEC)
, location=New Brunswick, Canada
, year=2006
, url=http://www.ntu.edu.sg/home/zhangj/paper/icec06.pdf
External links
Reputation Systems- 2008 tutorial by Yury Lifshits
- 2008 essay (book chapter) by David D. Friedman.
*
Technology in society
Social information processing
Social influence
Social networks
Social systems