And Prodigy, the online service, ran on Sears' mainframes that they had for scaling out Xmas sales but were mostly idle the rest of the year. The Advantis network was co-owned by Sears and IBM which was later bought out fully by IBM as part of their Global Network offering. I used to have an @ibm.net email address (which the network was then sold to AT&T and became attglobal.net)
Sears also used to sell entire houses (assemble yourself) from the paper catalog. They were massive!!!