You can rate a story from 1 to 5 stars, but the rating that gets displayed will actually have greater granularity than that. For instance, after multiple ratings a story could have an average of 3.78 out of 5.00 stars.
As usual, Internet Explorer is not as cooperative as Firefox (
A reminder, there's 3 ways to get to old stories. The best way is via the "Topics" link in the top navigation bar where you can browse all stories by topic. You can view stories using the "Older Articles" link at the bottom of the main page. And lastly, you can use the random story option by clicking the dice image in the top navigation and get sent to a random story.