Part of the problem, too, is that when you initially join something like Twitter, the only people seeing your posts may be a dozen friends, and then the size of that channel scales up, sometimes exponentially. It can be hard to track that and adjust your expectations accordingly. Historical posts can also be a problem because of this. If you're going to make in-jokes that would be offensive to the public, it could be a good idea to set up one of those services that deletes tweets older than a particular time span (months, years, whatever).