After playing with it for a bit I think that this is a TOTALLY rockin little tool for researchers. It has the ability to create different collections and sub-collections so you can track multiple research projects at once, automatically download available source info from websites, create links and snapshots of online resources. You can create notes and annotations for a page or book so that you always know what goes with what.
So anybody who's in school, or anybody who does research on their own should give Zotero a try. It might just be the best thing you don't spend a dime on. :)