Yahoo! Inc. (nasdaq: YHOO) is an American public corporation headquartered in Sunnyvale, California, (in Silicon Valley), that provides Internet services worldwide. The company is perhaps best known for its web portal, search engine, Yahoo! Directory, Yahoo! Mail, news, and social media websites and services. Yahoo! was founded by Jerry Yang and David Filo in January 1994 and was incorporated on March 1, 1995.

On January 13, 2009, Yahoo appointed Carol Bartz, former executive chairperson of Autodesk, as its new chief executive officer and a member of the board of directors.

According to Web traffic analysis companies (including Compete.com, comScore, Alexa Internet, Netcraft, and Nielsen Ratings), the domain yahoo.com attracted at least 1.575 billion visitors annually by 2008. The global network of Yahoo! websites receives 3.4 billion page views per day on average . It is the second most visited website in the U.S., and in the world.

Early history (1994–1996)

thumb|left|250px|Yahoo! co-founders Jerry Yang (left) and David Filo (right)

In January 1994, Jerry Yang and David Filo were Electrical Engineering graduate students at Stanford University. In April 1994, "Jerry and David's Guide to the World Wide Web" was renamed "Yahoo!", for which the official expansion is "Yet Another Hierarchical Officious Oracle". Filo and Yang said they selected the name because they liked the word's general definition, which comes from Gulliver's Travels by Jonathan Swift: "rude, unsophisticated and uncouth". Its URL was akebono.stanford.edu/yahoo. The original yahoo!® logo

By the end of 1994, Yahoo! had already received one million hits.Fact: date=April 2009 The Yahoo! domain was created on January 18, 1995. Yang and Filo realized their website had massive business potential, and on March 1, 1995, Yahoo! was incorporated. On April 5, 1995, Michael Moritz of Sequoia Capital provided Yahoo! with two rounds of venture capital, raising approximately $3 million. On April 12, 1996, Yahoo! had its initial public offering, raising $33.8 million, by selling 2.6 million shares at $13 each.

Like many search engines and web directories, Yahoo! diversified into a Web portal. In the late 1990s, Yahoo!, MSN, Lycos, Excite and other Web portals were growing rapidly. Web portal providers rushed to acquire companies to expand their range of services, in the hope of increasing the time a user stays at the portal.

On March 8, 1997, Yahoo! acquired online communications company Four11. Four11's webmail service, Rocketmail, became Yahoo! Mail. Yahoo! also acquired ClassicGames.com and turned it into Yahoo! Games. Yahoo! then acquired direct marketing company Yoyodyne Entertainment, Inc. on October 12. On March 8, 1998, Yahoo! launched Yahoo! Pager, an instant messaging service that was renamed Yahoo! Messenger a year later. On January 28, 1999, Yahoo! acquired web hosting provider GeoCities. Another company Yahoo! acquired was eGroups, which became Yahoo! Groups after the acquisition on June 28, 2000.