there are a lot of plugins out there to add this kind of functionality and
the one that i would recommend is Question and Answer Forum
which will get you closes to the example you link with no hard work.
main features:
- ask question form short code
- list question short code
- email admin when question is asked capability
- custom email to author of question when question is asked
- display of questions can be customised by theme
- spam filtering of questions
- dashboard widget showing last 5 questions
- user profiles including a tables with the number of questions, answers and best answers they have provided.
- best answers.