In May 2013, Ritz-Carlton Hotel Co. bought ads to promote its brand page on Facebook. After a few days, unhappy executives halted the campaign—but not because they weren't gaining enough fans. Rather, they were gaining too many, too fast

"We were fearful our engagement and connection with our community was dropping" as the fan base grew, says Allison Sitch, Ritz-Carlton's vice president of global public relations.

Today,...