Yesterday I found myself browsing through an old mail archive, and, of course, found lots of spam that I didn't have the time to delete back then. I noticed that the kind of spam I received was quite different from what it is now. For starters, it was clearly written, and mostly in latin characters. But the kind of things that were peddled were quite different. There was viagra, of course, and also assorted sex offers. But no colon cleaners, for instance (no tongue scrapers, for that matter. neither
It probably converts spam a collaborative filter for human lust and desires. Scams are usually built on desires (as well as ignorance, of course), and I guess that spammers use new "objects of desire" because they work better, and stop using others because they don't. For instance, it's been some time since I received the last nigerian scam. I've started receiving a russian equivalent, but none with "african" origin.
I guess somebody should built a "spam zeitgeist" index. It will be an invaluable resource in the future. The only thing they will have to figure out is why "1 Jan 1970" is such an important date for scams, and how they managed to bring Viagra from the future.