Well it looks like the busy guys over at surbl have created an interesting new feature.  They are now publishing spam domain totals based on most abused TLD's. This of course is rather interesting given the current state of the Registry world, and some of ICANN's ideas on new TLD's.  There is really very little surprise on the results of which domains are in the top 10, hopefully this sort of data will continue to spur the registry industry to look at implementing procedures to deal with abuse in their TLD's.  It should be noted that these figures are not tracking the volume of spam, but merely the number of domains that are seen in spam messages.

 Link to page:   http://www.surbl.org/tld-subtotals.head 

A quick quote from their website about this new feature. 

11/2/2009: SURBL has added a report of Most Abused TLDs. This is a daily count of the TLDs most commonly appearing in SURBL data and is an indication of relative abuse levels. The TLD .cn is disproportionately represented, most likely due to persistent and widespread abuse by the "Canadian Pharmacy" botnet-using spam gang.

Snapshot results as of Tuesday Nov 3rd 1:13 GMT:

237926	com
72591	cn
34818	net
18994	info
6986	us
3342	org
3329	ru
2966	at
1534	eu
1501	es
1265	biz
995	uk
941	in
687	sg
545	pl
432	de
237	im
216	hk
192	cd
175	cc