Yahoo!

Jerry Yang and David Filo were Stanford PhD students in 1994 when they began maintaining a directory of websites they found interesting — initially called "Jerry's Guide to the World Wide Web." They organised the links into categories, then categories within categories. The directory was renamed Yahoo — an acronym they claimed stood for "Yet Another Hierarchical Officious Oracle," though they admitted they mainly liked the word because its dictionary definition included "rude, unsophisticated, uncouth." By 1995, Yahoo was receiving one million page views per day.

In 1998, Larry Page and Sergey Brin approached Yahoo and offered to sell the Google search technology for $1 million. Yahoo declined — they were concerned that a better search engine would send users away from Yahoo's portal too quickly, reducing advertising revenue. Yahoo later had multiple opportunities to acquire Google at larger but still manageable prices. Each time, Yahoo declined. Google went public in 2004 at $85 per share.

Yahoo offered to acquire Facebook for $1 billion in 2006. Mark Zuckerberg was initially interested — he was 22 years old and the offer was extraordinary. He put the deal to a shareholder vote. It failed. Yahoo subsequently reduced its offer. The negotiation collapsed. Facebook was valued at $104 billion at its 2012 IPO and over $1 trillion at its peak.

Microsoft offered to acquire Yahoo for $44.6 billion in February 2008 — a 62% premium to Yahoo's market price. Yahoo's board, under pressure from CEO Jerry Yang, rejected the offer as inadequate. Microsoft withdrew its offer. Yahoo's stock, which had been trading at $28 before the offer, fell to $10 by the end of 2008 as advertising revenue declined during the financial crisis. Yang resigned under shareholder pressure. The rejection of Microsoft's offer is widely regarded as one of the worst decisions in corporate history.

Yahoo sold its core internet business to Verizon Communications in June 2017 for $4.48 billion — approximately one-tenth of Microsoft's 2008 offer. The sale was complicated by the disclosure of two massive data breaches: one affecting 500 million accounts in 2014 and one affecting all 3 billion Yahoo accounts in 2013 — the largest in internet history. Verizon reduced its acquisition price by $350 million following the breach disclosures. The company that had turned down $44.6 billion from Microsoft sold nine years later for less than $5 billion. Yahoo Finance, Yahoo Mail, and Yahoo Sports survived under new ownership. The search engine that had turned down Google had been replaced by it.