How do you stop people from asking and answering their own questions en masse?
You do realize that..
- you have to wait 2 days to accept your own answer
- you don't get any rep for accepting your own answer
Beyond that, is this really a problem in practice and not just in theory?
What's wrong with people answering their own questions?
OP stands no gain to answer their own question, other than to share with the community. You get no reputation for answering your own question.
By design, it's always been OK to ask a question and answer it yourself. One of the first SO questions I ever asked I did exactly that.
That said, over time, the social mores have changed a bit, and it's at least considered better form if you mark your own answer as community wiki such that you don't get rep from it.
In my opinion, this isn't a big issue. Other answers can come up and be just as good, and voted just as highly. It's not like the OP posting his own answer prevents others from posting theirs. And if theirs are better, the community will reward them.
in theory, i'm not even sure this would be a Bad Thing
in practice, it is never going to happen because Jon Skeet will answer the questions en masse before the masses can