Willis Tower KWO39, programmed by the National Weather Service Weather Forecast Office in Chicago, is equipped with Specific Area Message Encoding (SAME), which sets off a siren on specially-programmed weather radios to alert of an impending hazard, such as a tornado or civil emergency. The building has appeared in numerous films and television shows set in Chicago such as "Ferris Bueller's Day Off", where Ferris and company watch the streets of Chicago from the observation deck. The television show "Late Night with Conan O'Brien" introduced a character called The Sears Tower Dressed In Sears Clothing when the show visited Chicago in 2006.
Merchandise Building forces with Sears-Roebuck & Co. of Chicago in forming a 50/50 ownership in a new company, Simpsons-Sears Limited. The new firm took control of Simpson's catalogue and mail-order business and would open new Sears-style department stores in markets not already served by Simpsons. It was seen as better suited to take on competition with the strong T. Eaton Co. catalogue business and to use Sears marketing principles to expand into smaller Canadian rural and suburban markets. The Toronto Mail Order Building complex - which eventually came to be known by the less cumbersome name of "the Mutual Street Building", continued