Bewenched - 12:15 pm on Apr 8, 2008 (gmt 0) I feel your pain and I have lived it.
3. Duplicate content:
3c from sending bogus query strings to your urls
3d getting your site spidered under SSL
It's sad that instead of building good content I spend most of my time banning ip ranges of scrapers, bad bots and spammers and filing dmca complaints.
I feel your pain and I have lived it.