I do not think it helps in google. They are not direct links. You do have more links to your site but i do not think they help page rank.
Doesn't really help much in regards to better rankings, though your (and others) stumbles are linked to from pages there. The main benefit is alittle bump in Stumble referral traffic and some of those may blog or link to your site from forums if interesting enough.
I remember ages ago when I would see like LOADS of bots join on IRC channels and flood them, thats the same thing what stumbleupon reminds me to, a flood of visitors for a short period of time and than...poof it vanishes.
I do not think Stumble helps directly. Still indirect it can. If people like your site they will bookmark or might even post a link in there blog.
I have gotten listed in the engines on the reviews that were made on my sites. It helps a little and creates links but not a rare basis.
Stumbleupon will make your site popular if you have contents. But when it comes to SEO it only help your site get indexed frequently and it sends traffic to your site.
no, it dosenot helps to get your site indexed, actually stumble upon links are nofollow, so they don't help SEO cause!
Actually, while the effect is negligible, it does help in a couple small ways. Google users with the StumbleUpon toolbar installed will see the SU logo next to your site, with a link to reviews page. This can make you stand out in the SERPs if you have quality reviews. The review page itself will appear in the SERPs for your category, and could lead visitors to your site as a secondary presence. Also, while it is well known that SU links are nofollow, they do appear in my Webmasters Tools links, so I wonder about that. The traffic itself is like air.
as for my experience, this social bookmarking drives a lot of traffic to my site compared from any other bookmarking.
Based on my experience, sites will get very minimal (or maybe even none at all!) SEO benefits from SU. You'll only get some traffic and of course, site exposure. The traffic that you get aren't that good since they're not converting... the people don't buy your products, they just look at your site for a few seconds and they hit the "Stumble!" button again... Maybe it's just my colleagues and I, but I think that the benefits that you can reap from StumbleUpon really depends on your site's niche. Some few words on SU and SEO: Don't keep your hopes high, SU can't fulfill your SEO needs!
Yes it does not help your site be indexed, but it is better for traffic even if it is set to nofollow. It is better for Google because link juices are bad for them. SEO is not just about SE indexing.