I think that purchases on CGC boards are certainly a large portion of books. Probably not compared to Ebay, but I would think more than HA, Comicconnect and Comiclink combined. I think with GA books you just buy them where you find them. I do still try to go to LCS when I am traveling to see what is there and I still buy comics every Wednesday, though that is as much just for nostalgia and to keep long ongoing relationships with people I have known for many years as it is to get new books which I could do cheaper online.