Theory 1: There's nobody actually online but me, and it can take me a while to realise I'm talking to absolutely nobody. Then I stop talking, and other people come in and see no action.
Theory 2: We see someone come in we hate, and rather than ignore them because we're too nice for that, we stop talking
Theory 3: Underpants Gnomes
Theory 4: All of the guys are masturbating over all of the girls (can I really say that? I guess I just did) and all of the girls are hiding.
Theory 5: People forgot to add the chat channel to their viewable windows.
Edit: Hang on. So, masturbating isn't censored, but s****y is? Bad form, Mods!