As of now, how many people are online?
That said, the Report does provide best estimates: as of now, 48% of the world’s population is online. Regions obviously vary greatly: Europe is 80% online, Africa only 22%.
Of those not online, a significant percentage have feature phone access with texting ability (but no data — typically through 2G networks). According to a recent Facebook study of 75 countries, 94% of the overall population had access to 2G networks, where as 76% had access to 3G (data) networks or better. So as more users come online, many more current users will be upgrading from feature to smartphones as networks are upgraded from 2G to 3G.