While i was surfing on SO i saw many question solved but not mark as solved, what do you think is the right way to force the users who asked a question and got the right answer to mark it as solved ? There are many ways to do this, but most of them are unfair or can be used by "point's addicted" users.
My idea is, if the user don't visit anymore his question for long time (1 week, 1 month, 1 year) on the SO user panel, near the question have to appear somethink like that: it's your question been answered ? [Yes|No]
If it neither answer to this question for too much time the user have to be marked as leecher.