What are the things that D3 did right to get the acclaim, and why does it keep it for so long? d3 (especially now that they've broken the bits and bobs into d

What are the things that D3 did right to get the acclaim, and why does it keep it for so long? d3 (especially now that they've broken the bits and bobs into discrete packages) takes a very unixy philosophy: do one thing and do it well. d3 lets you iterate over your data and get useful items back (e.g. scales that you can use to create geometric shapes for a chart). It's intimidating for some but offers a ton of flexibility you don't see with other charting libraries. Mike Bostock also put a lot of effort into making sure that d3 lets you create beautiful charts. Every other charting library I've seen takes a very different approach. Often enabling you to create ugly, inflexible charts.