As of now I think stumbling is a part of social media marketing because social media is now use to market the site.
I still classify stumbleupon as SEO, the traffic you get from stumbleupon sucks. But the backlinks from people's profiles and the www.stumbleupon.com/url/XXX itself usually contain targetted anchor text and keywords. SMO SMM are all buzz words for SEO specialists to get an extra buck out of you. Most of it's hype, there isn't a great deal these people can do to help you out in the long run. Most of that information is freely available on the net and there is really no secret. Unless of course they have a power digg/stumble account, in which case they aren't optimising anything.
You can block the traffic if you really feel that strongly . Either through robots.txt or by contacting stumbleupon itself. (I think there is even a link on www.stumbleupon somewhere.)
It's fine, its only 3-6% of my daily traffic, they might click an ad anyways, plus the backlinks don't hurt.
Firstly you need to install the stumbleupon toolbar, then just go to the address you want the traffic to come to and click the upvote button. You'll need to review (submit) the site if nobody else has. Then stumbleupon will send a few visitors, if other users like it you will get more stumbleupon traffic. If people don't like it/don't mind either way you won't get any traffic. You can boost traffic by getting others to upvote your site/story/page. Just check the freebies section in B/S/T here on digital point and you are good to go.
SU as most other social web apps, is a tool for building your network rather than just being a tool for building traffic. Just because having a strong and active profile might not necessarily help bring you more visitors to your own blog or website, it doesn’t mean that the very same profile can’t help you brand yourself and making new connections.....The key to SU success is to create something people want to click the thumbs up button for… I’ve experienced the slight traffic increase from SU, but usually it only lasts for that long.... Narender Pal Singh
Im going to disagree with most of you here. I can get well over 10,000 - 15,000 unique visitors a month with a bounce rate of less that 40% - which is pretty good to be honest. I don't use it for a call to action but for providing information on blogs you will get readers and repeat visitors, so every time you press your thumbs up button you get a guaranteed number of visitors. I tend to get around 300-400 uniques within 3-4 hours of pressing a button. I would consider Stumble to be one of the few social bookmarking websites that can offer this kind of exposure.