- I write a new blog post.
- The link gets forwarded to Twitter.
- My Twitter feed in turn gets forwarded to Facebook and Buzz.
- At that point, I am equally likely to receive comments on Buzz, FB, or in the comments of the post itself.
The additional exposure for said posts is quite nice, because there are people on each site who don't pay attention to some of the other three feeds. However, it is tough to converse about a topic when the discussion is split three ways. Also, the blog posts themselves look a lot lonelier with the shorter comment threads.