By all means feel free just to chat in the guestbook - as long as it's not spam!
Anybody with Admin below their name is definitely me or a trusted person. I myself will always sign as Butterfree. If somebody signs under that name but does not have the Admin label, it is most likely an impostor.
The In-Game Humor page has a small mistake…
Near the end of the G/S/C section, it says that Missingno's type is Bird/Water… but it's actually Bird/Normal.
It does learn Water Gun (twice!), but it isn't an actual Water-type.