Have you ever been reading a website which references something you would like more information on, but don’t want to have to navigate to another site? If so, just look it up directly in a pop-up window using Cleeki.

With Cleeki your search experience can be as simple as one click on a keyword you would like to query. You leave the rest to Cleeki, which searches multiple websites automatically, intelligently and simultaneously. Retrieval results are nicely organized and returned to you instantly.

This free extension has both a Firefox and IE version, so it should accomodate most people. You can think this as an on-demand smart tag which isn’t annoying. You can read about all the features and watch a brief demo on their homepage.