Actually (*cough*) I'm signed up with a handful of the email survey sites. Most of them "reward" you by supposedly entering you in monthly drawings or something of that nature. I recently signed up with
GoZing and shortly after made a quick ten bucks for an IT survey. (They take up to eight weeks to pay, so I don't yet know if they actually come through or not.)
It's worth your time if and only if you actually enjoy spouting off your opinion to nameless, faceless strangers, and don't mind sparing a few minutes here and there.
Well now - new survey up, looks like I can make a $1.50 for sharing my opinion on household cleaners. Since it's 3:15 am and my brain isn't good for much else...