This year, eMarketer estimates, more than 52 million people in the US will use Twitter on a monthly basis, and just shy of half will use the service on both PCs and mobile devices. Mobile-only Twitter use is becoming more common in the US as desktop- based usage shrinks, and will account for a majority of US users in 2018 for the first time.
Currently, just 19.5% of internet users and 16.1% of the population of the US uses Twitter, compared with 51.5% of the population using Facebook. On a worldwide basis, Twitter penetration is even lower: Only 3.9% of people around the world use Twitter this year, and by 2020 the figure is only expected to rise to 4.8%. Read the rest at eMarketer.