Aggregate Users existing blog - example: projectopus.com

Hello,

I am new with drupal and need some help.

I'm trying to setup a site in which my user can register their current existing blogs (wordpress, blogger, myspace, movabletype, etc) and also create a "ranking" based on linking to my site. User will be able to embed a "badge" on their own blog in which will show their ranking from my site. I know this can be done with drupal or maybe there's a module on how to do this but I have not found it yet and figure that I should create this topic so someone can tell me the module name or how's the trick.

Basically the registration is almost the same like Project Opus: http://www.projectopus.com/user/fanregister

In which my user can add their blog rss on the registration page.

All help much appreciated.

Thank you.