Facebook and Twitter, among other social networking services, thrive on the status update. It’s a way of letting people know how you’re feeling, what you’re doing and where you are.
By nature, a status can reveal a lot of information about you and possibly your family. Be careful what you share (particularly in ‘real time’ — that is, when you post an update describing exactly where you are while you’re still there). Ensure your privacy setting is appropriately set (usually the “friends only” setting is sufficient) and self-censor what you’re about to post to ensure it doesn’t reveal anything overtly personal about your children.
Twitter by nature has a very open sharing policy, unless you have locked down your account. Unless your account is anonymised (i.e. it has no information which identifies you) avoid posting things which are extremely personal.