Creating visualizations is really only half the battle; the other half is getting high quality data to drive the visualization. There are a lot of potential data sources that you may wish to exploit. Almost every country has a national statistics organization tasked with gathering and analyzing economic and social statistics. In the past few years, many governments have begun adopting Open Data initiatives. Many businesses are also centered on providing usable data; think about the amount of data provided by various stock exchanges. You may even have access to internal company data you're using to drive your visualization, or your visualization may be part of a larger application that will provide you with data.
Another source, and the source we're interested in for this book, is social media. Social media sites have a plethora of data available to their users. The vast majority of social media sites provide APIs for accessing data in a programmatic fashion. Frequently, this...