A pink contract is an agreement between an email spammer and the spammer's Internet service provider. The contract exempts the spammer from the provider's terms of service, which typically prohibit spamming. In return, the spammer pays far more money for an internet connection than non-spammers.
"Any ISP in the United States can get in real trouble for signing pink contracts. Problem is that there's a whole big world wide web out there and the bulk of the pink contracts are signed with overseas ISPs where US Federal Authorities have absolutely no power."