What is Yahoo!?

Yahoo! is an Internet website portal. Yahoo!'s main service is its website directory and search engine. Additionally, the portal provides e-mail, instant messenger and chat rooms, personals, games, music, maps, website and photo hosting, shopping, news, and many other services. Yahoo! is the single most popular website on the Internet, according to web statistics aggregator Alexa, with almost one third of Internet users visiting the main yahoo.com site daily. Aggregated figures for Yahoo's international sites are not publicly available, however they are estimated to total close to the main site's traffic. Thus, two out of every three Internet users are estimated to use Yahoo! services daily.

Although Yahoo! is centered around its website directory and search portal, public statistics indicate that over four times as many users spend their time on the mail application than on the search application. In fact, the mail portal is more popular than the next 30 top Yahoo! services combined. Despite its success, Yahoo! Mail has been hit hard by longtime competitor Google's Gmail service, leading to a complete service redesign that is currently in public beta stages of development (as is Gmail). The new Yahoo! Mail uses an Ajax-powered interface that mimics the functionality of a local email client. While this places very heavy demands on the computer running it, it does work in all major browsers including Internet Explorer, Firefox, and Opera. Also, the old Yahoo! Mail is available to all users, including those who opted in to beta testing the new interface.

Yahoo! has often been criticized for including adware and spyware with programs they offer for download. The Yahoo! Messenger instant messenger client offers no option for disabling the installation of Yahoo!'s web browser toolbar. The toolbar is often criticized for providing no original functionality yet reporting on users surfing habits. Additionally, the toolbar cannot be uninstalled from Internet Explorer by conventional means. Other programs offered by Yahoo! that have been associated with adware or spyware include weather notification system tray icons, clock adjustment programs, and security-enhancement programs.