I just signed up for Stumble and plan to focus some time on this subject for a good week or so. Ill stop focusing any attention on stumbleupon and such after a week and in a month ill report back if there is still any traffic coming from these efforts. Lets see what happens!
You do realize that trading stumbles is against the stumble upon TOS and can result in your site being banned I hope. They can easily search forums, websites, blogs, etc to find sites trading stumbles, just some 2 cents for you.
StumbleUpon is coming down hard on those it deems to be abusing it's system. It's heavily policed by its own members. Good luck.
I never stumble for a stumble, I sent a review of 1 of my sites and had 100 stumblers hit it. I think it was because my site was based on a very popular topic.
yep, it used to be very easy to get thousands of hits from stumble, now its about well placed reviews... not just random 1:1 stumbles on the freebies section...