They are a rather unethical bunch IMHO and they are spammers. They also use telephone harrasment campaigns to try and get people to join up with them.
Trust me, I know from first-hand experince. I use a company called 2CheckOut and they keep calling me and e-mailing me over and over and over again despite my statements that I wasnt intrested and my requests that they leave me alone. Finally, I sued them for sending SPAM (illegal in Indiana) and they went away.
It was all very throughly hashed out in another forum... link to thead follows...
http://support.2checkout.com/forums/...300&boardid=18