I'm sure your HTTP logs, like mine, are full of 404 errors of various probes for common vulnerabilities and such:
File does not exist: /www/XXXXXX.XX/data/email File does not exist: /www/XXXXXX.XX/data/exchange File does not exist: /www/XXXXXX.XX/data/logon.asp File does not exist: /www/XXXXXX.XX/data/phpMyAdmin File does not exist: /www/XXXXXX.XX/data/vtigercrm
...and so on.
In the email world, one cool trick we can use is greylisting and/or tarpitting, forcing spammers to spend more resources waiting and/or queuing and retrying deliveries, possibly raising their costs and thus doing something good to the world. Also, later in the chain, tools like DCC/Razor/Pyzor do use feedback to a central site to make anti spam systems work better.
I'm now wondering if there is anything similar we can do to those nasty HTTP probes that could be useful or, at least, funny. Like HTTP Redirect them somewhere else... I guess most of the times the client won't follow the redirect but maybe sometimes it will, so we can send him to some honeypot, tarpit, or whatnot. (I doubt any human will ever see that redirect so redirecting them to some goatse won't have any coolness bonus :) )