The Short of It:
Facebook and Google are on a mission to prevent certain websites from telling falsehoods.
The Longer Version of It:
It's likely that you came across the many different news articles floating around the interwebs, specifically Google and Facebook during the presidential election and its campaign year. We're talking that Facebook ad that claimed both Pope Francis and Denzel Washington had endorsed Donald Trump. Not true. And that other store that said leading Google's search results claimed that Trump had won the popular vote. Also not true.
Both Google and Facebook use algorithms to decide what people see in their search results and News Feeds. With it, people are more likely to see websites and stories that are already getting attention. Throughout this year's election, it seems quite a bit of people were clicking on a lot of attention-grabbing stories that were also fake. So Google and Facebook have been got a lot of side eye for maybe helping spread false news that misled voters.
Earlier this week, both tech companies said they're banning fake news sites from using their ad platforms. Hint: tools that help other websites make some cash money by filling ad spaces on their pages. So this move could hit fake sites where it hurts...their bank accounts. But these actions won't actually stop fake stories from showing up in search results and News Feeds.
Your dad's right about what you read on the Internet. Don't always believe it.