User System

Hey

I was wondering if it is possible to add a little something to the wordpress system (maybe a plugin) that would keep all user functions the same but add just one little thing I need…

I want users to be able to sign up and have the ability to post to one specific category (user posts)… they don’t have the option to choose this category as it will be posted there automatically…

Also I would need the post to automatically be left off the main page… so all in all if a user comes to the site… posts something of internest (like a link/story/image) it is put in it’s category and people can browse that…. almost like b0g.org… ya know…

HELP PLEASE!