What is IM report card about?

It's basically your opinion and experience of whatever the site you're reviewing. At least that's how I write them and they get approved. Just don't get too opinionated. They're looking for more experience with the site then your opinion. Generally you have to have participated in whatever the site you want to write a review about or have had to have bought the product already before writing a review. So to answer your question in a lot of cases you have to have been a member of the site or bought a given product(to review those niche' product sites) & to answer your other question it's not based on what you read on the website or what others have to say, it's based on your personal experience.