Sooner or later you give away things about yourself. If you look at all my answers, for example, you'll eventually work out a fair amount of my taste in music, that I like sausage rolls, that I'm probably a bit left-wing and very much a preacher of tolerance, that I'm over 16, that I'm an asthmatic, and that I'm either male or a lesbian.
Or you could just read it here. And also, if you lie people figure it out...nobody really believes Ward~Minter about a whole range of things, for example.