We've had a spate of porno spam over the last few days and it has been targeted at recent posts rather than old ones. As much as some of you might enjoy following those links, it does not make for a good environment for discussion. As a result, we've gone to a "sign in" requirement for comments. It does make commenting one step more difficult, but we think it's well worth the cost, as do many other good Economics blogs.
Thanks for understanding.
The CP crew.