Do I need Multisite to get this functionality?

Hi everyone,

I’m clueless on how to get the needed functionality in WP.

I’m working on a multi-portfolio site where each user after registration should be able to create and edit a single page (post) in blog. They should also be able to put it in a category (of all the existing ones) according to their profession. They shouldn’t be able to edit comments, though.

How can I make this work? Is there any plugin that does that or do I need to set up Multisite? I need to add that it will be my first time with MU and that’s why I’m asking.

Thank you in advance,
Chris