MailBlocks is an e-mail hosting service company based in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, originally established by

Phil Goldman Phillip York Goldman (July 17, 1964 – December 26, 2003) was an American software engineer and entrepreneur. He was a Macintosh software engineer at Apple Inc., and was best known for co-founding WebTV. Early life Phillip York Goldman was born ...

in 2002. It was acquired by AOL on August 3, 2004.

Service

Mailblocks offered free challenge-response spam filtering web email service and an IMAP interface as a revenue service.

Patent Troll Controversy

Mailblocks did not invent challenge response to block spam. Instead, they purchased the rights to two patents related to challenge response: patent
US6199102
an
US6112227
Mailblocks then proceeded to

patent troll In international law and business, patent trolling or patent hoarding is a categorical or pejorative term applied to a person or company that attempts to enforce patent rights against accused infringers far beyond the patent's actual value or ...

several other companies before releasing any product of their own. Companies sued included Spam Arrest, DigiPortal, MailFrontier, and

Earthlink EarthLink is an American Internet service provider. It went public on NASDAQ in January 1997. Much of the company's growth was via acquisition; by 2000, ''The New York Times'' described Earthlink as the "second largest Internet service provider ...

. It is worth noting that challenge response was a well known technique for fighting personal spam and mailing list spam for years before the two patents were applied for. For example
David Skoll described it in detail in a post to a public forum on November 15, 1996

References

{{tech-company-stub AOL