I don't know of any other way to keep out the spammers other than to delete them as soon as possible. So if you see someone post something that seems somewhat unrelated to Follett, such as "Get Phenyldomdraline for cheap!," send me a message and I will dispatch them as soon as possible.
Looks like we just had a spammer invasion. I had to delete dozens of false-people. I'm not sure, but I think the only alternative to this periodic purging is to make the network "private" so that only invited people can join. If this issue continues, we may need to do that.