I'll ask the team if they're using anything special beyond d3/jq. The team is run by Lisa Strausfeld, an MIT Media Lab alum. You can also find videos of her talking about them floating around Youtube, etc.
That would be great, thanks. I suspected they were using d3, but based on how consistent some of their visualizations are with each other I suspect they have an in house library that they are using as well. Would be cool to hear from the source :)
JQuery Cycle is used for the IE<9 version, which is a slideshow of screenshots taken from the piece. Everything else is done with d3 and jquery as mentioned. We have a custom framework for these dataview pieces, all other work is just based on the same style guide. As seen here: http://www.bloomberg.com/visual-data/
They ask for
Experience in Javascript, JQuery, CSS, HTML, XML, HTML5
Experience in QGis, ArcGIS , Google Maps Api and large government open data APIs
Expertise in standard design tools (Illustrator, InDesign, Photoshop)
I work on the team, but didn't do this interactive, but I sit next to the guy who did. The other comments in this thread are correct, it's d3 and some jQuery. D3 is an amazing library and well worth learning. Thanks for all the feedback, we're reading it all.