OK; you've forced our hand. Here is what we're including as SPAM:

• junk mail, unsolicited material to persons or entities that have not agreed to receive such material or to whom You or Your end-users do not otherwise have a legal right to send such material;
• Any activities that violate anti-spamming laws and regulations such as the CAN SPAM Act of 2003 and the Do-Not-Call Implementation Act is prohibited

Obviously, this list is incomplete. If you can think of other examples, picture them being on this list, and then... don't do it!

(Actually, send us your suggestions, and we will add them to this list)