This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read at Oxford Scholarship Online and offered as a free PDF download from OUP and selected open access locations. As recently as the early 2010s, there were more internet users in countries like France or Germany than in all of Africa put together. But much changed in that decade, and 2018 marked the first year in human history in...