I've been blocked twice this morning, and removed myself once - the first time, by the time I got to work and looked at the list, it was already gone. My hosting provider works with those jerks at manitu. I've ranted a number of times over the years at why their method is a *lousy* method for blocking spam in the second decade of the 21st century.
Now this: here's another argument as to why the CentOS list should stop using them... when I went to remove myself, the email that told me I'd been blocked, also said who'd reported my mailserver (that is, hostmonster's mailserver) as sending spam was someone at selfip.biz. Go do a whois on them - it's someone at home, using dyndns, not an open obvious company. This means that anyone who gets annoyed at *anyone* served by any ISP can report them, and block everyone at that ISP.
Go ahead, tell me this is *reasonable* in 2013.
mark