spamhaus
 spam'hows, n.

    Pejorative term for an internet service provider that permits or even
    encourages spam mailings from its systems. The plural is spamhausen.
    There is a web page devoted to tracking spamhausen.

    The most notorious of the spamhausen was Sanford Wallace's Cyber Promotions
    Inc., shut down by a lawsuit on 16 October 1997. The anniversary of the
    shutdown is celebrated on Usenet as Spam Freedom Day, but lesser imitators
    of the Spamford still infest various murky corners of the net. Since
    prosecution of spammers became routine under the junk-fax laws and statues
    specifically targeting spam, spamhausen have declined in relative
    importance; today, hit-and-run attacks by spammers using relay rape and 
    throwaway accounts on reputable ISPs seem to account for most of the flow.