In January 1994, Stanford University electrical engineering graduate students Jerry Yang and David Filo created a website named "Jerry and David's guide to the World Wide Web".
Yahoo grew significantly (shifting from being a hierarchical listing of submitted sites to a search engine through the 1990s). By 1998, Yahoo was the most popular home page online. Yahoo stocks closed at an all-time high of $118.75 a share on January 3, 2000 but hit a post-bubble low of $8.11 on September 26, 2001.
In February 2008, Microsoft tried to acquire Yahoo for US$44.6 billion. Yahoo rejected the bid and proceeded to plummet in value to US$22.24 billion.
Marissa Mayer was appointed President and CEO of Yahoo in 2012 kicking off a slew of acquisitions including Tumblr, RockMelt, Brightroll.
Of the current stock price of $31: its Alibaba holdings are estimated to be worth $24, its investment in Yahoo Japan is worth $5 per share, and its current cash and holdings are worth about $6 per share… so the rest of it, the 5th most visited site on the internet that employs 11,000 people is apparently worth absolutely nothing. Huh? For more info, see the Wikipedia entry.