I use the Wiki module a lot and just noticed that the Wiki syntax differs between the Wiki-text resource and the Wiki module:
! Heading 1 (Wiki module)
!1 Heading 1 (Wiki-text resource).
I have no problem with it but just wanted to point to it.
(using Moodle 1.3.3)
In 1.4 this format has been renamed to Wiki-like format ... it's a completely different format invented by Howard Miller and predates the Wiki module. Unfortunately we can't reconcile the two formats now because there are undoubtedly pages all over the place relying on it.