Re: rate articles
For Wiki pages (don't know about articles):
Go to Admin > Features, activate Polls
You need to create a poll template for your rating in wiki pages. Do it. (ask if nedd help on this)...
Go to Admin > Wiki > Wiki Features, activate rating
As admin, edit a page, and go to "activate rating" (or similar, I'm talking by memory). Write a label, and then select the template to use for rating this wiki page.
Add perms to a wiki page so that your users (or user group) can rate the page.
...
Hope this helps...
xavi