Usergroups Explanation?

Hi,

I am new to wordpress, i already run a website which is based around vbulletin forum, i have now decided to use wordpress as my front-end. I want to integrate all users into one, for this i am using the vbulletin-wordpress bridge.

I am now at the stage where i need to map usergroups from vbulletin to wordpress… however i am slightly confused with what the usergroups mean, while the titles may seem self explanitory i’m not sure where i should be mapping them, i can’t see what privileges (if any) the wordpress usergroups give to the end user?

Administrator – this can be linked to admin group on vb

Editor, Author, Contributor, Subscriber… which of these is the standard level group? that i can give to ‘registered users’ on the forum.

I also have a usergroup which gives assigned members the priv’s to create news posts, so which group would this match on wordpress.. Author or Contributor?

on VB i also have Not Logged in and Banned.. which usergroup does this apply to on wordpress? i can’t see a banned group, surely i can ban users from posting comments?

Thanks ??