Well in a nutshell a man claims to have deciphered a crop circle found in England (next to a radio scope) that seems to be an alien response to the human template that was beamed toward M13 in 1974 from the arecibo radio telescope. The crop circle follows the same template, but tells us the same details about them as we sent out about ourselves. The man believes it is legitimate because this crop circle shows none of the usual evidence left when humans make a crop circle.
Personally I don't see why aliens that received our radio signal would respond in such a manner. Why not send us a radio signal in the same format as the one we sent out? Or better yet - since they're apparently already here to make a crop circle, why haven't they just openly made a personal introduction? Of course that question opens up many more debatable scenarios. Perhaps they realize that world wide knowledge of their existence would cause a lot of problems for our different religions and cultures as they stand in our present stage of evolution - so they're doing us a favor by avoiding that for the time being.