AOL: In 2006, AOL and its Chief Technical Officer learned the hard way that users do not appreciate disclosure of their online search activities. The company thought that it had properly anonymized the data when it posted online the search records of 500,000 of its users for use by researchers. It was wrong. The private search habits of AOL users became public knowledge. AOL quickly pulled the dataset from its Web site, but not before the information had been mirrored on Web pages around the world and AOL's privacy breach was plastered on front pages around the globe. The incident led to the firing of the researchers involved with the database's release and the resignation of the company's Chief Technical Officer.