The answer is a clear no. In fact, I recently noted some possible security threats by just revealing your DoB alone. Some more simple layman thoughts on it..(in this post I am not talking about technical vulnerabilities of the social networs; there have already been several exploits)
We are kinda addicted to social networks such as facebook, twitter, myspace etc. Social networks are great to get connected with old friends and stay in touch with friends and families. And also to be up to date with technology, news, what's happening around us and know what others are upto. We love interacting with others and being connected. There is nothing wrong about it; but there is a limit, above which it could be harmful. The whole network works based on trust. Just one weak link of trust is sufficient to cause all sorts of troubles.
a couple of examples:
social networks - physical security??? an interesting combination!
We have seen people tweeting or facebooking, where they are, what their vacation plans, etc. This could be good information for burglers -- we invite and help burglers to break in.
one social network - and the rest???
There are so many social networks out there..chances are that you are only in a subset of them. Say you are in Facebook and not in Myspace. What does it prevent a bad guy from impersonating you in Myspace? Further, the impersonator can trick your friends to be her friends.