This seems to be new behavior (possibly to stem losses to StackOverflow?). Several months ago, they did not display answers, even when coming from Google. At

This seems to be new behavior (possibly to stem losses to StackOverflow?). Several months ago, they did not display answers, even when coming from Google. At some point before that, they displayed answers overlaid with an image to make the answers hard to read. They were pretty obviously experimenting to find out what kind of annoyance would convince free users to sign up.