Brightmail Inc. was a San Francisco–based technology company focused on anti-spam filtering. Brightmail's system has a three-pronged approach to stopping spam, the Probe Network is a massive number of e-mail addresses established for the sole purpose of receiving spam. The Brightmail Logistics and Operations Center (BLOC) evaluates newly detected spam and issues rules for ISPs. The third approach is the Spam Wall, a filtering engine that identifies and screens out spam based on the updates from the BLOC.
Brightmail had partnerships with major Email providers and ISPs including Netscape, Sendmail, Hotmail and Software.com. Other partners include AT&T WorldNet Service, Concentric Network, EarthLink, Excite, FastNet, FlashNet, Juno Online Services and USA.net.
The antivirus-inspired regular update mechanism used to detect spam email attracted the attention of Internet security software makers and Brightmail was acquired by Symantec in 2004.[4]