The biggest surprise in the retail world this week was the announcement of a new partnership between Forever 21 and Shein. The fast-fashion rivals, both of which specialize in throwaway clothes for teens and twenty-somethings, have agreed to cross-promote each others’ brands. Forever 21, which dates back to 1984, is a mall-based retailer with a longtime location at Westfield Montgomery. Shein, founded in 2008, is a Singapore-based business that sells almost entirely online. Both companies have been criticized for reportedly exploitative manufacturing practices that allow them to sell clothing at such low prices — but both continue to be wildly popular with young shoppers. If this partnership comes to fruition, Shein fans may soon be able to try on their outfits in person at Forever 21 stores.