I'm actually working on another addition ot the site, a social bookmarking section that will allow my visitors to sign up to like 80 social bookmarking sites at once. There really isn't anything you can do to stop such mass uses I think, at least at the moment.
My only problem that I'm having so far is working on a module that enables visitors to even post to many/multiple sites at once and not just one.
It is the extra fields that stop me - choosing the category since most sites have different categories. It is not impossible though. I will update you and tell you when you can check out the module on my site EarthFrisk.
Give me just a week and it should be done. along with my social bookmarking section.
Mike
http://www.earthfrisk.com