Ask Jeeves–the fourth most popular U.S. search engine after Google, Yahoo!, and MSN Search–will be acquired by Barry Diller’s IAC/InterActiveCorp for $1.85 billion, IAC announced today. The acquisition is a huge and presumably happy milestone for Ask Jeeves. The company has struggled for years to find its place in the search-engine market, at times coming close to bankruptcy, but has experienced a marked resurgence over the past two years since scrapping its old search technology in favor of the Teoma search engine. IAC also owns other major Web destinations such as Ticketmaster, the Home Shopping Network, and Expedia.

Meanwhile, weeks of rumors ended yesterday as Vancouver, BC-based Ludicorp, creator of a community photo-sharing site called Flickr that has become an underground sensation in alpha-geek and blogger circles, confirmed on its blog that it will be acquired by Yahoo!. Many of Flickr’s social-networking features will be added to Yahoo! Photos, but Flickr itself will continue as an independent site, according to the blog. Anticipating wails of discontent among loyal users, Flickr’s management emphasized that “We’re going to stay true to our vision and to the people who made us what we are– that’s you, the Flickr pioneers.”