Mark Zuckerberg vows to 'fix' Facebook
Mr Zuckerberg has famously set himself challenges every year since 2009. Facebook launched in 2004.
Social media firms have come under fire for allowing so-called fake news ahead of US and other elections to spread.
Facebook in particular has been criticised for allowing Russia-linked political ads in the run-up to the 2016 US presidential vote.
Mr Zuckerberg said he intended to focus on "important issues", which he listed as "protecting our community from abuse and hate, defending against interference by nation states, or making sure that time spent on Facebook is time well spent".