I think the better, more relevant question is will humans become obsolete when AI becomes smart enough to ask and answer its own questions.

At some point, everything becomes obsolete so I definitely see a time when musing and quora fall into that category as well. Will be at the point you mention or will there be another catalyst or milestone, that I cannot say.

When AI becomes smarter than its creators, a lot will change. Will AI begin to hoard its knowledge from us and make us second class citizens? Begging to learn new things or have knowledge given to us in drops as we now do in order to teach the AI? Will the AI simply make all knowledge readily available to us anytime we ask, similar to what internet search engines do?

There are a lot of questions surrounding exactly what will happen when the machines eventually surpass us. And I believe it will happen at some point, after all they do not have the same limitations we do, so why would it not happen?