Incorporated in 1995, Yahoo! Inc., is a global Internet brand best known for its online search engine and advertising business. Nearly 20% of all online search traffic uses the Yahoo! portal and users in the tens of millions make Yahoo.com their homepage. Yahoo!'s revenue comes primarily from its online advertising business, much like that of Google. The company also drives traffic to its own site through its affiliate program, where third-parties integrate Yahoo!'s advertising into their own sites. Yahoo!'s advertising offerings can be summarized into 5 categories: Front Doors; Search; Communications and Communities; Media, and Connected Life. Each category offers its own blend of web services and application programming interfaces (APIs), technical resources, tools and channels to market. Yahoo! rejected takeover bids from Microsoft in both January and May of 2008.