The Web site started out as "Jerry and David's Guide to the World Wide Web" but eventually received a new moniker with the help of a dictionary. The name Yahoo! is an acronym for "Yet Another Hierarchical Officious Oracle," but Jerry and David insist they selected the name because of its definition: "rude, unsophisticated, uncouth."
The original Yahoo logo which stands today is bright red in color and went well with the uncouth definition. The Yahoo philosophy back when the site was created was to be very quick and so possibly the simplicity of the logo went with that philosophy. Over time, the logo has changed and there exists a purple version.
Some of the other variations include the Y! Bang logo or the Yahoo Messenger logo.
Yahoo Red Logo
Yahoo Purple LogoReference: http://yhoo.client.shareholder.com/press/history.cfm http://en.wikipedia.org/wiki/Yahoo!