Block redirect code
I just checked a random blogspot spam URL. It had a working redirect. And I realized several webservices could block by a pattern I recognized:
This is the code for document.location:
100, 111, 99, 117, 109, 101, 110, 116, 46, 108, 111, 99, 97, 116, 105, 111, 110
Spammers usually change it, so it might look like this:
100!111!99!117!109!101!110!116!46!108!111!99!97!116!105!111!110!
Scan and block by that pattern, and you tag quite a lot of spam, but not all