Actually it fits the Steem blockchain perfectly.

Some thoughts:

• all data can be on chain
• voters vote on answers directly so the authors can get author rewards
• for good questions, the ones who asked them can also get author rewards
• voters would get curation rewards, vote relatively early to get more %
• A reward from the author is also awesome
• appropriately use tags so the questions can appear on the trending page of steemit.com
• Use json_metadata to do deeper classification (credit: @good-karma) so you can play with them on your site