I like the quiz idea. But I don't think the questions a t the bottom are necessary. The only problem i have with people using stuff like ur,2, etc is when the us it too much in one post. Also if someone uses your or there the wrong way the post is still readable. If you miss too many of the questions you have to wait x number of hours before you can post. But the user taking the quiz would be warned that if they mass to many they'll have to take it a gain. The paragraph with the rules should also show some good and bad post examples like these:
Good: I really like your build but I think you need to use more bricks.
Bad: ur build really suck i give you 1/10