One of the earliest take aways from the global financial crisis was the importance of access to information for effectively functioning financial markets. And, in that regard, credit ratings can serve an incredibly useful role -- in theory.
John Carney's New York Times op-ed piece is a tour de force, a paean to nonsensical thinking. He ignores the Fannie and Freddie of the real world. Instead, he goes after the Fannie and Freddie that exist only in his imagination.
CDOs remain shrouded in secrecy, their financial reports remain hidden from public view, unavailable to anyone except actual CDO investors. Bloomberg's coup was to pierce that veil of secrecy, and to drill down into the details of one CDO.