I know I could just copy and paste what Stumble Upon is from their website or another resource, but I rather say what I think it is. I do not promote that what I say is always 100% accurate. Stumble Upon is like a search engine that looks for similar categories and interests that you provided when signing up with them. With that, you can either rate it the website with a thumbs up or thumbs down. In addition, you can leave comments which is community like and starts a rapport with other users.
In my experience, I have use Stumble Upon to promote one my websites that I made. One of the first steps I did was sign up which is free. Then I got to play with the application and see what I like and did not. Here is what I did:
1) Signup
2) Added my Website as a favorite. (To do this I believe you simply go to your favorite link and enter your website address.)
3) Then I started to click on the stumble upon graphic and it took me to similar interests and categories. Every day for about 2 weeks I favorite 10 sites I like and commented what I like or did not like.
4) In doing Step 3, I realize users where clicking on my username (I believe its a backlink in web terms) and it took them to my site.
5) Warning! I also want to explain that searching for a site you like or has a particular interest in things you like can sometimes be time consuming and even take the whole day and still see no significance results. On the other hand, it can lead to new visitors and gain more interests. In addition, you might find interesting stats if you install google analytics on your site.
