Having registered users post anonymously

[Xenon]

it's not that easy.

the easiest way would be total annonym posts by just don't saving the userid and the username into the post, but then they can't edit the posts anymore.

but it's a secure method.
the other way like mist said is also possible and they can edit the posts, but it's insecure, because the names could be seen when searching and so on...