As Safe Teens On Line says
The most important thing to remember is that when you’re online in any kind of a public forum, you’re out in public and anyone can read whatever you post. You should never post anything on the Internet that you wouldn’t want known to the public at large. You should also remember that people you meet in cyberspace might not be who they seem to be. If you’re in any type of public forum, avoid giving out your full name, your mailing address, your telephone number, the name of your school, or any other information that could help someone determine your actual identity. The same applies to your family and friends. Never reveal anything about other people that could possibly get them into trouble. The biggest danger to your safety is if you get together with someone you “meet” online. Remember, you never know for certain if people you meet online are who they say they are. If you do feel it’s appropriate make sure the meeting is in a public place and bring people with you.
I don't want to be a party pooper. I am sure that all those who turn up will be nice blokes and blokesses, but I'm not sure if my making a point of going all the way to Cardiff to meet with strangers in the Vulcan would give a very good example to my boys. So sorry I won't be there!