Welcome from me, cohrt
You're right about people not being too willing to share about who they are, but there is a "middle way" if you like: not too much, not too little.
If someone is so anonymous that you have no idea where in the world they are, what sex they are, who they are ... just a vague screen name that reveals nine tenths of absolutely sweet naff all, then I'd agree.
On the other hand, it's unwise to share such personal details as your phone number, address, and anything else that could personally identify you.
Each person must choose their own level of anonymity, but I like to know that the information that is shared is at least accurate. Certainly I'd rather see no information than wrong information!
So ... I don't have any problems with people knowing my real name, age, sex, an approximate geographical area, some likes and dislikes, etc. but I wouldn't put anything onto the open Internet that would allow people to track me down as that could open me up to all sorts of abuse.
As an aside, on another forum someone started a disucssion pertaining to the idea of using a "male" avatar when you're a female, or vice versa ... it was a shortish discussion, but quite lively and informative at the same time.