I just discovered something interesting. If I hit reply to a toot, it's the time at which I do that that counts as the time I made the toot, and not when the toot actually sends (when I hit the TOOT button).
That seems like a slight oversight that would likely get rectified, I'd hope. (I mean, I can imagine how to abuse that, and I'm not a knowledgeable exploit finder. I'm sure someone better versed in abusing bugs could go strange places with it.)