Mark Zuckerberg's New Year resolution: 'Fix' Facebook in 2018

Chief executive has set annual personal challenge since 2009; in post, says company 'has made too many errors'

For years, Mark Zuckerberg has announced an annual personal challenge, from slaughtering his own meat to learning Mandarin to building his own artificial intelligence.

His 2018 task might be the most ambitious yet: Fix Facebook Inc.

In a Facebook post Thursday that highlights his company’s mounting difficulties, Mr. Zuckerberg said the social network has made “too many errors enforcing our policies and preventing misuse of our tools.” The Facebook chief executive, a self-described optimist about technology, said promising tools such as encryption and cryptocurrency could help counter concerns about the growing power of technology giants, but added that they, too, carried risks