[koolba]

That's because you got fooled into making an account. It's trying to get you to complete the registration process so they can pick questions to show you.

If you clear your cookies and go from a Google search result to Quora, you can read the answers on the page that you're on. If you navigate to any other question, say via the links at the bottom of the page for similar / related questions, the answers will be blocked by the signup popup.

If, instead of signing, you go back to Google and search for the same "<question> quora" it'll work again. The thing to remember is only the first page you navigate to from Google will display properly.