I also think that it might make a lot of sense to put that piece into the Syndication Links plugin as well since that’s a piece that directly relates to something Brid.gy is looking for to do backfeed. Doing this may also make even more sense if Syndication Links becomes a tool for POSSE as well. It would be nice to have a definitive one-stop-shop for syndication and backfeed related functionality.
As a “throw-away” aside, if you’re looking for a good name for such a thing, perhaps Boomerang? Throw your content out there and all the responses return back to your site?