Among the multitude of add-ons available for Firefox, there are a handful which change the way you browse the web permanently (Greasemonkey, AdBlock, PONG, etc). Hyperwords definitely deserves a place on that list for the way it adds interactivity to any word on any web page. The plugin works simply: select any word or block of text and you’re immediately offered a menu which lets you pick a command to use with that selection.
The list of commands is pretty impressive, ranging from Google searches to in-line translations to a sort of ‘Blog This’ functionality. These functions are individually available in a multitude of plugins, but Hyperwords brings them all (and a lot more besides) into one simple menu. It also avoids siding with just Google sites by offering a wide range of sources and web apps to choose from.
It has already been backed by some pretty big names but if you’re still not convinced, try out the demo page before installing. I reckon that this could be the best extension I’ve ever tried, in terms of the way it opens up the web in such a simple, usable way. Hyperwords rules.