I censor myself on many levels. People rarely see what I think of as the "real me". Okay, I know, trite, but stay with me.
The most visible level, on a site like this, is the fact that I don't use a spell-checker, and I write in complete sentences. Not "incomplete sentences"; I checked. :-) Anyway, this little editor stays busy while I type, which I can do fairly rapidly after a year-long class in high school. It serves me well as a professional typist, that is to say, as a software engineer.
Another level is my selection of content, which lately involves consideration of things my wife wouldn't want me to talk about. Not that I exclude them all, of course, otherwise it would be right quiet around these parts. But I do take her feelings into consideration, unless they are overruled by a larger need of my own. (At least, that's what I tell myself.)
Which brings us to the third level: censorship of my own feelings. The person talking to you is intensely logical (or at least, that's what he tells himself.) He tries to relay the thoughts of the whole me, but he doesn't really understand all of them, which results both in selection errors (he chooses less important things to say) and misinterpretations (he says things his way, which is not necessarily exactly what I meant.)
And no, I don't experience this as a true dissociation. There are not separate personalities, or "voices", or anything. There are just ... parts of me, specialized for different things. And most of them arrested at about seven or eight years of age.