From what I’ve read about Fav.or.it (if anyone has an invitation let me know!) you can write comments within the fav.or.it platform and they are written back to the blog itself.
One of the things I like about Friendfeed is the commenting, but quite a lot of feedback and comment on Friendfeed will never be visible against the original media. It would be good if Friendfeed did the same as Fav.or.it and wrote comments back to the source and attributed those comments to me. Perhaps using a some sort of FF prefix – "Tom commented via Friendfeed:….".
This would be good for the end users as their comments would be more visible and attributed to them, and probably quite good for Friendfeed as comments on blogs, flickr etc. would spread the FF word.