Spam is an interesting thing. For instance did you know that right now this website is receiving at least 10 spam comments a day? It's a small fry compared to larger sites. Often spam rarely makes sense at all? Why post spam comments to old entries on a blog no one reads? There's not even a pagerank argument there. Regardless spam it is and dutifully I have been deleting the comments and configuring the anti-spam filters each day.
What's interesting is how an arms race develops. I block their names and they change them. I block them on the text of comments and they mutate them. I block by their website url and behold, those adapt. So I add a time limit on new comments. The same number of comments appear but spaced out. I block comments from the same person for more than an hour. The spam appears posted by different people. They say about 90% of the internet is spam(or was it porn) and most of it appears nonsensical. How are random comments a good business model?
Yet someone falls for scams. Someone buys herbal viagra. I'm availing of this brilliant offer for a brand new PC if I just send a cheque in the mail.