Although there is the risk of bad things happening both on-line and IRL, it seems that on-line communities tend to be stalker/creep magnets and of course the ladies are at risk by far more than men.
Protect your personal information as if it were a bank vault full of gold.
I'm one of those people that says don't hand out phone numbers, addresses, personal e-mail (since for many they contain your name), Facebook info, and full name (first isn't a big deal, but last is dangerous)to on-line friends until you know them VERY well. Once someone has your full name and the city you live in it's pretty simple to find an address, it's the same for phone numbers because reverse searches can be done. Even personal info such as extremely personal things you wouldn't want others to know about can be used to extort additional information you wouldn't want to give out (we've seen it happen here).
If you choose to communicate with other users off site either use a "dummy" e-mail that you only use for those purposes, or if you want to actually talk with the person use Skype (don't use your full name on the publicly available profile).
If you choose to actually meet someone in person, do so at "neutral ground" such as a restaurant or other public place. Even better is to meet in a group setting as many have done since it adds to the level of safety.
Although we as a site do our best to keep the site clean and safe, there is not much we can do once someone begins to cyber-stalk. Sure, we ban them but someone with minimal tech intelligence can get around IP screening and get back in endlessly as some have found out recently. Once it reaches that level it becomes an issue for the authorities, and interstate crimes like that can be difficult to prosecute.
As other have already said, pay attention to that feeling in the pit of your gut at all times.