Autoposter services?

[Kathryn K.]

Does anyone know what, exactly, these services are? From what I gather, you can send out ads or articles en masse to newsgroups, ezines, email addresses, etc. I really know nothing more than that. Do these services have the newsgroups and ezines already in a database or is it that you have to build your own database and the system helps you manage it? I would like any info or feedback on this as I have heard that there are some people using autoposter services to market properties.