Ever wonder what it would look like to plot every single geotagged tweet since 2009 on a map? Twitter has done just that.
Twitter posted these maps of Europe, New York City, Tokyo and Istanbul on its blog Friday. They use billions of geotagged tweets: Every dot represents a tweet, with the brighter colors showing a higher concentration of tweets. It's pretty amazing how the mapped-out tweets clearly match with population centers, highways and the like — though perhaps that's obvious.