Facebook Inc. is backing away from efforts to sell ads in WhatsApp, in a retreat from a controversial plan that drove the creators of the popular messaging service to resign more than 18 months ago, according to people familiar with the matter.

WhatsApp in recent months disbanded a team that had been established to find the best ways to integrate ads into the service, according to people familiar with the matter. The team’s work was then deleted from WhatsApp’s code, the people said.

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