Online merchants are forcing even the highest-end stores to offer up bargains to their well-heeled clientel who are relatively insulated from the job and housing markets. “At the luxury end, discounting has become very mainstream because of the Gilts of the world,” said Andrew Sacks of luxury research firm AgencySacks, referring to Gilt Groupe, the online discounter for designer fashions. At the height of the 2011 holiday season, Bergdorf Goodman’s website listed more than 70 pages of discounts on designer fashions, some marked down as much as 40 percent. Bergdorf Goodman has also turned to digital and social-media programs in recent months, launching campaigns aimed at building the brand’s presence online, including a contest inviting its Facebook fans to design a Fendi handbag. While Bergdorf isn’t the first luxury retailer to try a user-generated design campaign, it may be the first to board the crowdsourcing bandwagon.