Unlock the true power of what you do by building friendships.
However if used correctly sites like Stumbleupon especially can be used to gain a ton of traffic. The key is building relationships.
On stumble for example, by searching through members you will find people who have massive amounts of friends and subscribers. They are the people who post the most sites and get viewed many times.
If you can strike up a connection with some of these Stumblers, the future value of these relationships can be huge.
Imagine connecting with an experienced Stumbler with hundreds of subscribers, and having them Stumble one of your sites for you. Do you think that would attract more eyeballs than your simple incidental "backlink" Stumble?
The key is to find a connection or common interest and build from that. IMO to use these sites just for links is a waste. Think long term. Building relationships will help build your business.
Hope this makes sense to someone.
Just when you think you've got it all figured out, someone changes the rules.