Google on Monday announced it is shutting down the consumer version of its online social network after fixing a bug exposing private data in as many as 500,000 accounts.

The U.S. internet giant said it will "sunset" Google+ social network for consumers, which failed to gain meaningful traction as a challenge to Facebook.

Facebook on Tuesday said hackers who stole digital keys to tens of millions of accounts appear not to have tampered with third-party applications linked to the social network.

Facebook engineers analyzed logs of outside applications and found no sign of trouble, according to product management vice president Guy Rosen.

Facebook on Tuesday stepped up ways to battle bullying and harassment at the leading social network.

The initiative calls for new tools and programs to help users control "unwanted, offensive or hurtful experiences on Facebook," global head of safety Antigone Davis said in a blog post.

The EU's top data privacy enforcer expressed worry Tuesday that Facebook had lost control of data security after a vast privacy breach that she said affected five million Europeans.

Three scientists on Tuesday won the Nobel Physics Prize, including the first woman in 55 years, for inventing optical lasers that have paved the way for advanced precision instruments used in corrective eye surgery, the jury said.

Tesla has promised to revolutionize the automobile, but the high-end electric car maker keeps hitting road blocks created by its founder Elon Musk's erratic behavior and considerable ego.

Facebook is at the centre of controversy yet again after admitting that up to 50 million accounts were breached by hackers.

Facebook announced Friday that up to 50 million accounts were breached in a security flaw exploited by hackers.

The leading social network said it learned this week of the attack that allowed hackers to steal "access tokens," the equivalent of digital keys that enable them to access their accounts.

A majority of U.S. teenagers say they have been victims of online harassment or bullying, and that social media companies aren't doing enough to fight the problem, a survey showed Thursday.

The co-founders of Instagram are resigning their positions with the social media company without explanation.

Chief Executive Kevin Systrom said in a statement late Monday that he and Mike Krieger, Instagram's chief technical officer, plan to leave the company in the next few weeks and take time off "to explore our curiosity and creativity again."