Basically a travel search site. Unlike most other travel sites, they don't do the actually selling. Think of Kayak as Google but with a niche - travel. They comb the web for the cheapest air tickets, best vacation deals, lowest hotels prices and allow you to search with your own criteria. With a very simple to use interface, this is probably one of the little website "gems" for travel buffs. Of course it is not perfect, but at least it gets the results. They have apps for iPhone, Blackberry and Android, so you can easily access the site on your mobile device.