The premise is to make money - sorry if you can't take it at face value. If it is so troubling, I would suggest you block referrals from SU.
Don't get me wrong. I am a big fan of capitalism. I believe that people deserve to get paid for their work/service/efforts. I was simply trying to add two things to the discussion: 1. Earlier in this thread, someone that had been using stumbleupon for years didn't know that some of the sites they were seeing were paid placements. I was trying to show this was true. I can take things at face value. It just appears they are not showing that face to their users. (or perhaps the users don't care.) 2. I was also trying to address the title of this thread: "Stumbleupon.com trafick, is it clean?" If some of the traffic is clean and some of it is paid, what does that mean to adsense publishers? Does that put this traffic in a gray area with Google? Is it a big enough source of traffic that adsense publishers should be concerned? I certainly don't mind the exposure to Stumbleupon visitors. My sites don't make enough money from Adsense to be terribly concerned about the traffic quality. I am just trying to contribute to the discussion. Cheers.
Good point about AdSense. I don't see a gray area in regards to AdSense - I would say that SU is clearly against the AdSense TOS, so people should be concerned about it. Yet another variable that the AdSense Publisher cannot control and Google could (if it so desired), but will not. It is much easier to place the responsibility (no matter how difficult) on the Publisher. Excellent point that I had not thought about.
Yes, you can have paid placement on StumbleUpon. http://www.stumbleupon.com/ads/ I have done it before - got over a thousand visitors within half an hour but I didn't get any conversions. Some of them rate and review your site though.
As far as I can recall, you can choose traffic within broad categories e.g. cars, electronics (I think people who use stumbleupon specify their interests when they set it up). The users are more looking for interesting websites than wanting to buy anything.
When I'm using StubleUpon (toolbar mostly), I barely spend more than a few seconds on the website whilst I think "am I interested in this site in the slightest..?", 9 out of 10 times, I just click to Stuble again. So in that respect, Google wouldn't be too happy.
Exactly. Goodness knows I love Stumble, but the toolbar really puts it in danger of violating the AdSense TOS.