Quora is its content. Its content is user contributed. Hiding such content from other users is just plain evil.
Which is why I'm sure there's going to be something new coming along one of these days: something where users are in control of what they post (e.g. not a wiki unless the user who did post does accept himself others' edits).
Collaborating to answer questions is fine. But modifying and closing questions artificially (due to very serious moderators issues) isn't acceptable either.
So I'm waiting for the next big thing and I'm sure it shall come.
Quora is hiding answers to make you sign up.
I agree, it isn't any worse than one of the biggest examples of biased, overzealous, insular, clique moderation online. I think setting our standards a little higher than that is pretty reasonable though.
You know what you're getting into when you post on a Stack Exchange site. If you don't like it, then you're okay to not use it.
Not like when you post on Quora. Do they tell you that your answers will be blurred and hidden behind a login-wall?
But really, the best programming joke hidden in source code is nothing more than noise. There are other places for that. When you want to cram that into Stack Overflow, then you'll have problems with its moderation.