Here's a basic question about using StumbleUpon to increase traffic to your site: Why do you need friends? If you submit a good article from your site and it gets a fair amount of thumbs up, isn't that when your article will get "ranked" on stumbleupon and you'll get an increase in traffic? How do friends come into play so prominently? Thx for any insight...
:\ It's how the system was set up and works. It's a big "you scratch my back, I'll scratch yours" ploy as StumbleUpon is sort of all over the place for most users (though fantastic when set up properly). As with most, if not all social networks, your page gets higher prominence if it has more connections/"back links"/is a networking hub on its own. The more central to the social spiderweb you are with more threads spawning off you than the corners, the more views and higher rank you'll get.
Here's the part I'm missing though: how do your stumbleupon friends give you the equivalent of 'backlinks'? What action(s) would they perform or what keys would they hit?
I guess the internal algorithm places greater value on your submissions if you have more friends. More friends - more traffic directed to your sites automatically.
If your friends list is huge so there is a button where people check out received pages by their friends so when they check out it will give you traffic.
There is a share option in Stumble upon, If you have long list of friends, you might share able to your sites to all friends and get more traffic as well if they are review your site then you get the one way link also.