Valleywag was blacklisted early on, and Gawker has been too at least as long as Valleywag has been reintegrated into it. Plenty of other domains are blacklisted too: http://infoworld.com has been for some time, http://oppugn.us/ got added fairly recently, http://www.kungfugrippe.com/ got added after a (wholly justified) rant about Scribd (YC S06!).