I would like to see this introduced in Bitcointalk forum.

Quiz/test knowledge messages can be used for:

- Registration  (to prevent bot/spam users asking them to read forum rules and basic Bitcoin faq, and then answer them)
- for Ranking Up  (extra way to rank up with answering quiz/test of knowledge)
- preventing users break forum rules (by educating them with quiz/test and rewarding with merit if they pass)

It can be useful for:

- educating users
- preventing spam/bots
- improving merit and ranking system
- improving Bitcointalk forum