Whereas Facebook’s strategy has always been to keep users within its own ecosystem, Twitter content is scattered all over the place, and this makes it difficult for the company to provide an accurate measurement of its userbase. Somewhere around 300 million people use Twitter actively, which is significantly smaller than Facebook’s 1.5 billion active userbase, but that doesn’t account for people viewing Twitter content from somewhere that isn’t Twitter, which is a massive amount of people. According to Twitter CFO Anthony Noto, measuring Twitter’s actual audience would likely put the company on a level that’s comparable to or even exceeds Facebook.