I've used Tableau to create visualizations for years. It's a great tool, but there are problems with it. It takes a long time to render in the browser. The learning curve is steep for some of the mapping and network visualization things that I want to do. As with many menu-driven point-and-click programs, an interface designed to make things easy actually makes it hard to see what's happening beneath the hood. Enter D3:
D3 renders in the browser almost instantly, at least for simple charts, and it has given rise to a burst of creativity the developer community. Here's my first attempt: a chart showing the frequency of use for each letter in the alphabet, based on the WordPress-d3 For Dummies tutorial for the WPD3 WordPress plugin.