Create checksums based on URL content?

Lately, more and more spams are getting past FUZ2 (at least for me) as they
include horrific amounts of random words (I can only assume this is the
cause, after looking at the ones that get through).

I used to see 1 spam a week, or less (in concert with SpamAssassin), but I
wake up to several each day now.  (I get about 100-200 a day total).

What would be involved in adding a feature to DCC where it loads the content
of the URLs in a message and computes one or more checksums based on the
content of the linked sites?

This would have the added effect of wasting traffic on the spammers' sites.
The spider could have a low timeout of say, 10 seconds, so that if a site
was being hammered by other DCC users it would just assume it was a spam URL
and file it as such.

Whitelists could be used somehow to avoid hammering legitimate sites.

Is this possible?