There are many new users I helped on Stack Overflow. They say thanks, but they don't accept (mark) answers as they are not aware of it.
So there should be proper introduction of Stack Overflow to new users. They should be taught about Stack Overflow step-by-step, like taking a tour on Facebook.
The introduction should be done as the new user logs in for the first time, and it should be mandatory to run the introduction session.
And a link should be there to re run the introduction session whenever the new user wants.