One of the world’s largest advertisers is threatening to pull its ads from social sites such as Facebook and YouTube if the tech companies don’t do more to minimize divisive content on their platforms. Unilever’s chief marketing officer, Keith Weed, will call on Silicon Valley on Monday to better police what he describes as a toxic online environment where propaganda, hate speech and disturbing content that exploits children thrive. “Fake news, racism, sexism, terrorists spreading messages of hate, toxic content directed at children – parts of the internet we have ended up with is a million miles from where we thought it would take us,” Weed plans to say in a speech at the Interactive Advertising Bureau’s Leadership Meeting in Palm Desert, California, according to prepared remarks.