I noticed today that one of the links in my top commentators plugin list was to a sex site. I knew this was wrong as I know the commentator listed and his link has always been fine. After not finding any reason for this, I went to the Akismet spam que and deleted the spam from the past 2 days. Once I did that his link was back to correct.
So one of the spams in the Akismet que was causing his link to change to the sex site. How was this possible?