The BBC must be a trusted voice in a "post-truth era", the director-general has said.
With rumours spreading round the world quickly on social media, people need a news source they can rely on, Lord Tony Hall added.
Addressing the Voice of the Listener and Viewer autumn conference, he said: "I want to talk about ... the BBC as a trusted voice, in a crowded arena.
"Increasingly - in a world of infinite information online, where a rumour can travel the globe in the time it takes to type 140 characters - people need to know what they can trust.
"We're told that we have now entered the "post-truth era" where presentation can override facts, and where it can be hard to separate truth from conjecture.
"But the real truth is, it has never been more important to be able to separate facts from opinion, prediction from certainty."
Citing the corporation's coverage of the EU referendum, Lord Hall told the conference: "The British public put a premium on authoritative, impartial news coverage. And that's exactly what we're here to provide."
Lord Hall also told the conference the BBC had to "earn the right to be heard" as it made a case for itself during its charter renewal after confidence in the corporation was shaken in the wake of the Savile inquiry.
He said: "We had to take a long, hard look at our culture.
"Faith in the corporation was profoundly shaken by the Savile inquiry and a BBC that badly let down the survivors of abuse.
"Thanks to the important and challenging Dame Janet Smith report, we now have the policies in place we need as safeguards for the future.
"And we will continue to take every possible step to make the BBC more open, challenging and collaborative - one of the very best places to work."
Looking to the future, he said the BBC aims to create a Netflix-style service to showcase its wide-ranging radio content globally.
Describing it as a "Netflix of the spoken word", Lord Hall said the service will strengthen the ways the broadcaster shares its audio archives to reach a wider audience.
"It's one of the things that will help the BBC carry the full weight of Britain's culture and values, knowledge and know-how to the world in the years ahead. And say something really important about modern Britain," he added.
This will follow the path of the broadcaster's iPlayer service, which allows viewers to catch up on TV programmes online, and other streaming services such as Netflix and Amazon Prime Video.
More details about the service are expected early next year.
Netflix chief executive Ted Sarandos previously praised the BBC for launching iPlayer in 2007 and paving the way for other on-demand services.