I'm not sure if it was ORBS or another one of
those blacklist
"services". In any case, it was blacklisting all domains belonging to
SPRINT and SPRINTnet. I found out because our company uses or used
SPRINT as its ISP, as do millions of others. It turned out that this
was done on purpose.
I concluded that the people running that blacklist are utter morons,
and since then I have seen similar idiotic actions either by that same
outfit or by others like it (for example, blacklisting
adelphia.net
smtp servers because one Adelphia customer sent spam via that server).
They're not morons, they just have a ruthless attitude about companies
that won't enforce their own AUP. That's how Sprint got whole IP blocks
blacklisted. It likely never would have happened had they actually gone
after the spammers lurking on their networks.
g.