It seems customers are ready to go online to buy Calder sculptures, Van Gogh and Persian rugs. Sotheby’s and eBay plan to announce today that they have formed a partnership to stream Sotheby’s sales worldwide. Starting this fall, most of Sotheby’s New York auctions will be broadcast live on a new section of eBay’s website. Then comes online-only sales and streamed auctions taking place anywhere from Hong Kong to Paris to London.