Why does so much of my spam have spelling errors?

I have often wondered this myself, with spam messages like "YOU JUST WONT A GREENCARD" (don't they mean "won"?), "Morgage ref id last opportunity" (don't they mean "mortgage")? and, my favorite "earn a college degre instantly" (they presumably mean "degree", but if they can't spell the word degree, how can I have confidence in the legitimacy of what they're offering??)

But anyone who has spent more than about five minutes looking at the problem and attempted solutions to spam knows why there are such rampant misspellings: to try and sidestep spam filters. In additional to individual spam filtering systems, there are now many Internet Service Providers who filter your email before it even gets to your mailbox, weeding out the most idiotic and easily recognized of this junk.

Of course, if you are a physician and have patients who are concerned about that Merck Vioxx prescription you wrote for them two years ago, it is theoretically possible that their message won't make it to you. If you're a mortgage broker, well, news of your competitors offerings might be something you do want to receive. But overall, most people don't want this junk, so the people clogging up the Internet with the billions of spam messages sent daily continue to try and sidestep these filtering mechanisms, and the misspellings, typos, and oddly presented words (like "0ffer" with a leading zero rather than "offer" with a letter o) presumably offer some minimal ability to do just that.

The irony of all this, in my opinion, is that the more spammers try to do overt and stupid tricks to try and sidestep the filters, the less effective their messages are. They might measure 1 sale in 250,000 messages a success, but better targeting, legitimate offers, well-written ad copy and genuine opt-in distribution lists might just improve those odds quite a bit. And if you're selling something, wouldn't you like to avoid having 95% of the Internet spontaneously hate you because of your marketing techniques?

What do you think? What heinous or hilarious spam subjects have you been seeing lately in your inbox?