[exim] Market Share?

Stats - imperfect, but with reasonable disclaimers - and quite interesting w/r
the share of detected Exim vs other MTA.

http://www.oreillynet.com/pub/a/sysadmin/2007/01/05/fingerprinting-mail-servers.html

No interest in arguing the merit/lack therof - the information is what they were
able to do 'on the cheap', and the methodology is therein described.

But has anyone seen any other recent studies (flawed or otherwise)?

Bill