It's not so much the fact that they are revealing it but the fact that they don't namechange! Writing intimate details about family, relationships etc. and coupling this with photographs on their profile which make them easily identifiable... isn't it just asking for trouble? Some people on here are very easily traceable in real life, and have posted things about how horrible their husband is, sex life, child issues, money issues - all under the same name!
I just think it's not very sensible and leaves you vulnerable to people either just winding you up or setting out to do something truly malicious. Or do people really not mind strangers knowing more about them than most of their friends?