If u like to chat with strangers, then u have to give some sort of info away about yourself - otherwise u won't be able to chat at all.
So what info is ok and what is suss?
If u set boundaries on things that u don't want to talk about, it might make u more aware of people who want to step over those boundaries. Weirdoes are very clever at changing conversations - they start by getting to know bits about you and only gradually introduce stuff they really want to talk about.
It's generally ok to talk about this kind of stuff:
Your age
Your sex/gender
Your hobbies
Your opinions on stuff
But mind the stuff that lets strangers see where u r:
Work, school, college or home address
Names, nicknames and especially surnames
Mobile or landline phone numbers
Chatting about places u like to hang out
Think about boundaries for stuff that will tell a stranger who u r:
Your real identity (photographs, mobile images)
Problems u might be having at home, school or with yourself
Your thoughts on sex and sexual stuff
Remember: just because u r online and chatting, it doesn't mean u r anonymous. People can use lots of online directories and other search tools to piece together information about u.