It was started by the GSFN (getsatisfaction.com) tab. Although this one isn't GSFN.
Actually, I'm pretty sure the UserVoice folks started it. When we added it to Dawdle (still there), the GS folks didn't offer one.
I have been wondering about that damn Feedback tab for a while, thanks for letting me know who to blame.
Blame all you want, but it's been invaluable to us. We have a Help link on every page, which goes to Contact Us (i.e. an extra step), but for whatever reason, the signal on UserVoice feedback is much higher than messages sent via our Contact Us form.
Sorry, its probably just my setup, but those tabs really distract me on a lot of websites. I am however glad they helped you... I just wish they didnt stand out so much, though that would probably defeat the purpose.
I dislike those feedback tabs with a passion. I find them incredibly distracting.