In-stream reserve ads allow advertisers to choose content packages in specific categories, including sports, fashion and beauty, entertainment, food and news. These are also purchased in advance at a fixed cost.

Twitter just announced plans to keep a closer eye on political advertising throughout European Union member states, Australia and India.

That finding -- included in a new report from Sprout Social -- suggests that consumers are looking to brands to rise above the current state of cultural discourse.

For Facebook, additional threats could come from new engagement platforms like Fortnite and Twitch, which bring consumers together in ways that Facebook doesn't.