This week MapBox released a series of dot map visualisations of Twitter data. The maps explore every geotagged Tweet since September 2011 "revealing demographic, cultural, and social patterns down to city level detail, across the entire world."
My personal favorite visualisation is Mobile Devices, a dot map displaying the brand of phone used when people use an official Twitter application.
The map reveals a really interesting pattern across American cities that seems to suggest that the iPhone is more popular in higher socio-economic neighborhoods, while Android phones predominate in areas with lower socio-economic residents. In business neighborhoods the Blackberry seems to be the device of choice.
Across the rest of the world there doesn't seem to be such a split in the economic level of Apple and Android device owners, while the Blackberry seems to be popular in business areas across the globe.
The Locals and Tourists map highlight areas of cities popular with locals and places where tourists visit. The map shows the locations of Tweets sent by locals (those who post in one city for one consecutive month) and tourists (whose tweets are centered in another city).
This map provides a fascinating insight into locations that are popular with tourists. For example, in this screenshot (above) of my neighborhood in London you can clearly make out the 2012 London Olympics stadium.
Languages of Twitter is a map that displays where different languages are used in Tweets. Different languages have been given a distinct color on the map. One obvious use for this map is to visualise areas with large immigrant communities.