I used to use it heavily, but I stopped when I moved to Chrome, since at the time it didn't have Chrome support and even now it feels hacky. Worth noting that

I used to use it heavily, but I stopped when I moved to Chrome, since at the time it didn't have Chrome support and even now it feels hacky. Worth noting that SU traffic may be unusually low-engagement, since I would think it's likely a user will just click Stumble again after the half a second or so you get to grab their attention. (That's an educated guess, mind you--I don't have any data to support this beyond how using SU felt to me.)