Claria Corporation (formerly Gator Corporation) was a software company based in Redwood City, California that invented “Behavioral Marketing”, a highly effective but controversial new form of online advertising. It was founded in 1998 by Denis Coleman (co-founder of Symantec), Stanford MBA Sasha Zorovic, and engineer Mark Pennell, based on work Zorovic had done at Stanford. In March 1999 Jeff McFadden was hired as CEO and Zorovic was effectively forced out.

Its name was later used interchangeably with its Gain advertising network, which it claimed serviced over 50 million users. Claria exited the adware business at the end of second quarter 2006, and eventually shut down completely in October 2008.

The "Gator" (also known as Gain AdServer) products collected personal information from its unknowing users, including all websites visited and portions of credit card numbers to target and display ads on the computers of web surfers. It billed itself as the "leader in online behavioral marketing". The company changed its name to Claria Corporation on October 30, 2003 in an effort to "better communicate the expanding breadth of offerings that [they] provide to consumers and advertisers", according to CEO and President Jeff McFadden.