How Does StumbleUpon Make Money?
I’ve been seeing a decent amount of questions regarding how StumbleUpon makes a profit.
SU profits in 2 ways: Sponsors, and Sponsored Stumbles. Read on to find out how each of these affects you.
Sponsors
In SU, you have the option of donating a certain amount of money (suggested $20 for a 1 year membership), and you get a cool green icon instead of a blue one next to your name. Additionally, you can start groups, get messages emailed to you, as well as turning off sponsored stumbles.
Sponsored Stumbles
How else does SU make money? Every once in a while, a site that you’re taken to is there because an advertiser paid $.05 to bring you there. This site will generally be related to your interests, and you can’t tell the difference. Generally, less than 2% of all Stumbles are sponsored.
I hope this answers some of the questions you have about how StumbleUpon makes its money.

tom
wrote @ 5:55 pm on July 1, 2007:I doubt stumbleupon traffic converts much, so it must be to get a positive ROI even at $.05 per visitor