Just to clarify: most servers haven't K:lined the blocks, but D:lined them (even though the efnet.org article says 'klines'). K:line = kill line, D:line = deny line. The difference is where the check happens, after the client has had a chance to identify and a identd response is received or not, or at the TCP level on remote IP address alone (D:Line).

D:Lines are less resource intensive obviously. Not much difference for the client though :)