This would be easy to implement: apply page layout of question creator, like background image, colors, etc. The only problem with that is: some Twitter users have really ugly background images and ugly color schemes. That's what holding me back from implementing this feature.

Check if page viewer is following question creator and if not, then add "Follow this user" button
This is easy to do and use javascript api, no auth required for that

Need to add pages to see user stats like "total points", "questions answered", "when joined", links to 'questions created', avatar of cause.

How about notifying question creator that '100 people answered your question' and a link to page to see that question stats (who answered and how)

But people must be able to opt-in to be notified first

This is the place to suggest new features for our site qod.tw as well as to tell us if something on our site is not working as well as it should