"They might as well recapture some of that market share by signing up with a travel search engine like Kayak." AOL was quick to point to Kayak's impressive online travel DNA. The Norfolk, Conn.-based company is run by the founders of the three big Web travel sites, Orbitz, Expedia and Travelocity. The news comes as online travel exerts an increasing hold on the imagination of growth-starved tech investors. Online publisher Travelzoo ( TZOO ) has turned into one of the market's unlikely heroes this year, posting a 1,000% rise based in large part on hopes for the industry and the company's thin float. Travel services giant Cendant ( CD) last month sewed up an agreement to pay $1.2 billion for Orbitz, and was slated to complete its acquisition Friday. But the growing investment in online travel services has meant increasing competition as well.