We’ve featured a number of search aggregator sites over the last few months and it is fair to say that the majority of them can be fit into the same square box. Parts of Sitdex can also be fit into that box, including being able to tab between Google, Yahoo, and Amazon for searching. The difference with Sitdex is that it adds a social layer to the process, thereby creating a more intelligent and constantly improving search engine. With Sitdex you can favorite sites right from the search page, email them to friends, comment on the site, see how many people have clicked on it, and get a thumbnail preview. Sitdex also only gives website results, so you don’t have to filter through erroneous hits on your search.