I hit a comments milestone today: 100 comments made on my blog. Mind you, that includes my own pingbacks (i.e. where I put a link on one post which refers to another post or page) and my own replies to comments, so the number of real comments is lower than that. Still, it’s the way WordPress tracks things, and it’s a pretty number.
By contrast, however, in the same period of time, I have received 1,392 spam comments. So, only 7% of commenters have something worthwhile and/or relevant to say. Make me wonder if only 7% of my traffic is legitimate too.