I never got it, just visitor come and gone, ^_^ Social community doesn't garantee that we will get click, but unique IP and visitors ok, a lot more, but click, no more
Stumbleupon isn't a waste of time.. it helps with PR, traffic does come in ... and it is low agree but this is the same with most social bookmarking networks.. *sometimes*
Everything, wondering if you can share your experience how does that improve PR? What i have seen that stumbleupon visitors dont even stay on your site for 1-2 mins. They are always in a hurry to stumble to next site. Do you think they are even interested in looking at your content and giving you a backlink? Please share your experience..it could be different
I got a few backlinks from Stumble showing on Google. I am not saying it is great but for the little time it takes, it does have some benefits. Any time your website gets shown, there are chances that you will earn something. I have several sites that I visit regualr that I found through stumbling. So I wouldn't rule it out, just use it as part of an overall plan and it's free so what have you lost?
Recently stumblers started coming in + I invested some money for targeted visitors for specific country and age group but, those are just visitors interested in certain topic... no change in adsense earnings, infact the earnings have dropped slightly (I guess google is going through THAT part of the month again...) I usually seek traffic for the websites it self rather than hope they are going to click on my ads.