I never noticed this before, but if you put a URL in when you’re commenting on my blog, it doesn’t actually put the URL in there, but rather puts in a URL for a local redirection CGI that will send you to the correct place. I wonder if that’s to stop comment spammers from getting the Google PageRank points that they’re trying for? I don’t remember this before, so I wonder if it’s something that came along when I upgraded to MT 2.661, or when I installed MT-Blacklist.
I see that Misha’s blog, which uses an older version of MT, doesn’t seem to have this feature.