Scoble points us towards CoComment, which lets you bookmarket where you comment, aggregate and publish conversations and ping you with updates. This is a common practice for delicious users as a service, and a reminder that Web 2.0 is really just re-inventing email with backlinks and pings.
Recently Stowe Boyd suggested that having more comments/trackbacks than posts was an indicator (Conversational Index) of a popular blog (although he didn't back it up with traffic data, but his call on it is good enough for me).
Wasn't long ago that comment and trackback spam made comments unbareable. Heck, still is, less today, more tomorrow. But I still have real comments I've yet to get back to as an author (Hi Pierre).
Happens that today the NY Times has the news of an economic solution for email spam offered by AOL and Yahoo. There's the old business plan again, put a price on your inbox. Still makes sense if you can get past adoption risks. Noise is only reduced through cost.
Attention begets attention, but at the cost of time. Time spent in signal is the best indicator of success.
