Idea for a new plugin

I have been looking ofr a plugin where users can save their favorite articles and files for future reading.

I found this http://nxsn.com/my-projects/wp-favorite-posts-plugin but I dont think it supports MU. This would be a great plugin if it could track across MU blogs and can be shown in a users profile.

Also would be good if you could do a widget like "Most Saved".