A recent map of Twitter usage shows where in the world usage of the popular social media network is heaviest. Not surprisingly, the Twitter map looks a lot like a NASA image of the world at night, with major cities everywhere lit up brightly, and with much of North America and Western Europe blazing with light. But the usage pings mobile phone use of Twitter, which lights up countries such as Indonesia. Heavy use areas such as Japan look weirdly dark at times, mainly when they are sleeping while North America is busy hashtagging everything it can think of. One thing is for certain, though: If you’re still not engaging some form of social media, Twitter would not be the worst place to start. Everybody is on it. Unless you live in Africa.