Thanks, sebg, for submitting this!
The main difference between this and some other heatmap charts is the UI design, and the fact that is a 1 year moving window of day aggregated data. Thanks for sharing all of the other heatmap examples in the comments, many of which I haven't seen before.
This is still in the early stages so if you have any questions or suggested improvements, just comment them here - I'd love to hear them!
This project seems to just be for daily data while cal-heatmap can do different levels of aggregation. I guess the flipside is that this project looks a bit easier to call and is probably lighter.
This is nice! I once attempted my own heat map type control that didn't use d3. It didn't look too bad but it fails pretty hard at the edge cases of having too many labels, etc and it doesn't look the prettiest. I think my next attempt will use d3.
Oh I feel I should mention there is yet another d3 based heatmap that I'm actually working on using right now. Plottable.js. Here are its examples: http://plottablejs.org/examples/calendar/
I like this and had just started to integrate it into my project when I saw that in Firefox it doesn't render completely. The month and day of week labels are cut off: http://i.imgur.com/CrZyEUt.png (that's the example code from the github project.) I like the simplicity of it compared to the other options.
http://bl.ocks.org/mbostock/4063318