Think of it like a cross between Digg and Facebook but for SEO and SEM types.
It's also a bit like Bumpzee.
I don't think though that they are that affiliate marketing friendly. Even though they have online marketing and affiliate marketing categories, I submitted some good stories that don't even show up.
I feel snubbed.
An example of how to use it would be to submit a good SEO related story.
If people like it they Sphinn it (Digg it) and it rises to the top to get more eyeballs.