I noticed today that the IP range for one of the default name servers for registerfly domains is now listed on SBL
http://www.spamhaus.org/sbl/sbl.lasso?query=SBL45242
This includes dns2.registerfly.com but not dns1.registerfly.com. If any of you use SBL listings of name servers for making decisions whether to blacklist suspect domains, be careful not to cause false positives!
In any case I hope registerfly will get the message soon and kick off the spammers who've been registering masses of domains through them which are spammed via botnets.
Joe Wein