A catalog of the world's largest archive of popular music — which includes gems like Keith Richards' old blues records – is going online. The materials at the ARChive of Contemporary Music in Tribeca will be available for public inspection under the agreement announced last week with Columbia University. The ARChive includes more than 2 million recordings, 3 million photographs, books, press kits, videos and memorabilia. Pop music lovers won't be able to listen to the music online, but the catalog will provide authoritative data about the sound recordings in the collection. The archive includes the world's largest collection of sound tracks and film scores.