incrediBILL - 2:32 am on Jul 15, 2012 (gmt 0)
It's more than just that, some are spamming, some are attacking.
Not all of the sites are just spam links, some are malicious.
FWIW, I'm getting tons of this stuff lately on a couple of sites. All reports I wrote have now been verified to be HTML sanitized and I shut down any log analysis and reports that I didn't write for security.