How do you do business on sites like Plaxo?

I have been a member of Plaxo, (a business networking site), for many years.
I have had invitations to connect and sent invitations to connect to others.
I decided I would invite a few business women to join our network. After 10 e-mails I was stopped and then I received an e-mail telling me that I was not behaving properly and am risking being blocked.
What on earth is that all about. Has anyone had simliar experiences?