Mine's not a scam.
Depends on the source, really. Oftentimes they're legit. Like if you visit Yahoo or Intel or Boeing and something comes up asking you to participate in a survey of the site, most of the time it's legit and helps them to improve the site's functionality. I got one on Delta the other day too.
I love them. I love surveys because it gives one a chance to become part of the process...your votes contribute to helping improve something. I always participate.
But others are less legit. Such as on popup and ad-rich websites where you get something that says "Take our survey and claim your $10,000 prize!!"
Those are not legit. Again, review the source.