Over the past decade, we've seen a rise of a multitude of travel booking sites, Hotels.com, Expedia, Orbitz, Priceline, those damn Travelocity Gnomes and Hotwire, all vying to get you the best deals for your trip. Then came Kayak, with a mission to help you make sense of it all. And TripAdvisor, for those essential customer reviews. But if you thought Silicon Valley was done with travel, you're wrong. The last few months have seen a resurgence of interest and investment in this rich vertical, sparked when Microsoft began integrating KAYAK technology into Bing.com/travel, the offshoot of the search, erm, decision engine, back in March, to continue to build on proprietary technologies like their "Price Predictor," which they had begun developing as early as 2009, in their attempt to differentiate their search service from Google. Much of the innovation behind travel search is powered by ITA, which Google acquired last summer for a nice $700 million, which will power a Google-ITA evolved travel offering is imminent, and it will be interesting to see how that affects the other players and competitors in this space currently leveraging some form of ITA technology. Get the full story at AdAge