The only danger in relying on friendfeed is that it was bought.

Otherwise I'm curious of what algorithms or measures you used to score shares?

I am working with another developer on a semantic/social processin application. We use external trending sites for search a well as Twitter search API with JavaScript. I think value comes from helping to make new connections, or raising interesting content from friends that may have been missed.

Check VictusMedia.com if you're curious (next patch is adding some groovy features once bug smashing phase is cleared).