You can still sign up for Quora accounts without a social network OAuth. I just did. It asked for my email, firstname, and lastname.

When you post questions or answer, you can also click the "anonymous" checkbox to remove your name.

The problem with reddit is that it's hard to ask random, potentially "dumb" questions. You have to find the right subreddit, and if you're wrong you'll just be downvoted and receive joke responses. Even in the right subreddit many questions will get instantly downvoted by people browsing /new/. Quota has none of these problems.