Hyperwords - Never go to a search page again!

"Do useful things with all the words on a page, not just the links."

Hyperwords is a selection-based research tool. According to the site, "The point of Hyperwords is to make every single word on every single Web page usefully interactive..."

To use it, select any word on any web page, then select from over 300 commands - Google search, Flickr search, Wikipedia, YouTube, Twitter, email, blog, translate, etc.