I think the concept has potential, so i worried that my negative reaction was simply a knee-jerk opposition to anything new. My objection would be assuaged if only the little pop-up gave something truly useful.

Mouseover links seem to be the new detritus on the information superhighway. The ones that show up in the text of email messages on Yahoo seem to be actually useful; however, when they show up under random words and phrases on various other pages (often with the text stolen straight from Wikipedia), they seem... i don't know, kind of alien, like the product of a non-human intelligence.