I’m not sure if the instructors grade the exercises or not. The members definitely do though. If you click on any of the categories (Blender/Concept/Unity) there’s a drop down on the header of the page that says “Exercises”. You can either browse through the different exercises if you’re looking for something to do, or you can click “View Submissions”. That will pull up all of the exercises that other members have done, and you can go through and grade them if you want, or just check out what the did.
I’m not big on the whole members grading members thing. I’d prefer it be an instructor, but they already have enough on their plates. I wouldn’t mind it if there were some way to have it be people that have already completed the course/exercise and passed it, that are aloud to grade. Because there are a lot of people that just go through and grade just to gain xp or they haven’t completed the course that it corresponds with. I’m sure I’ve submitted some that shouldn’t have passed, but they did.
I do like the exercise concept a lot though. It helps get you out of following step by step mode, and gets you to start problem solving on your own.