• by Wendy Davis  @wendyndavis, March 6, 2014

Facebook's proposed $19 billion acquisition of messaging app WhatsApp will “violate WhatsApp users’ understanding of their exposure to online advertising,” two privacy groups said in an FTC complaint filed on Thursday.

“WhatsApp built a user base based on its commitment not to collect user data for advertising revenue,” the Center for Digital Democracy and Electronic Privacy Information Center writes in its FTC complaint. “Facebook routinely makes use of user information for advertising purposes and has made clear that it intends to incorporate the data of Whats App users into the user profiling business model.”

The groups allege that the fast-growing messaging service's prior promises that it wouldn't “retain or repurpose” users' data spurred some consumers to sign up for the company. “Therefore,” the organizations write, “WhatsApp’s failure to adequately disclose that this commitment to privacy was subject to reversal constitutes a deceptive act or practice.”

The advocacy groups are asking the FTC to halt the deal pending the resolution of concerns about privacy. Alternatively, the groups say that if the deal goes through, the FTC should require Facebook to “insulate” WhatsApp's data about users.

A Facebook spokeswoman says the deal will help the company to “bring more connectivity and utility to the world by delivering core Internet services efficiently and affordably.” She adds that WhatsApp “will operate as a separate company and will honor its commitments to privacy and security."

The deal also faces the possibility of scrutiny by regulators in Europe, where WhatsApp is especially popular. The company already has run into trouble abroad. Last year, Dutch and Canadian officials said WhatsApp violated foreign privacy laws by requiring users to share their contacts' mobile phone numbers.