Top 25 Web 2.0 Search Engines

Online search is now a multi-billion dollar industry, with Google alone grossing over $3.5 billion in profits last year. It's no wonder why so many newcomers are hopping on the search bandwagon, hoping to become the next Google. And those new search engines that may stand the best chance to become the next Google all share one common element — the use of Web 2.0 technology that they hope will increase search result relevance.

Here are 25 such engines. Some offer functionality that's slowly making its way into traditional search engines. Others further the attempt to traverse the invisible Web and index other previously unsearchable research sources.

Top 25 Web 2.0 Search Engines