The desire to peer into people’s lives is one of the reasons that Google launched Plus in 2011. It was supposed to be a challenger to Facebook’s social network, which now has more than 2 billion users. But Plus flopped and quickly turned into a digital ghost town, prompting Google to start de-emphasizing it several years ago.

But the company kept it open long enough to cause an embarrassing privacy gaffe that could give Congress an excuse to enact tighter controls on data collection.

“Every data mishap strengthens the bipartisan case for Congress to take action on data protection,” said Jonathan Mayer, an assistant professor at Princeton University who formerly worked in the Federal Communications Commission’s enforcement bureau.

Europe began to impose tougher online privacy regulations in May. Those rules also include disclosure requirements for data breaches. Those rules don’t apply to the Plus problem because Google discovered it before they took effect.