A True Interaction Model
The most highly requested Polychart.js feature was interaction, and so we built a flexible, event-based interaction model straight into Polychart.js. This is a truly unique feature of Polychart.js. When high level charting libraries call themselves "interactive", they typically refer to simple interactions like displaying tooltips on mouseover. Polychart.js's interaction model goes beyond that, allowing developers to create custom interactions, and even allowing multiple charts to interact with each other, like below (see code for these charts here).
Simple Data Aggregation
Polychart.js uses Raphael.js internally for SVG rendering. Raphael.js falls back to VML in older Internet Explorer browsers, and still works on tablets. This means that your interactive charts can be viewed by almost anyone.
The code is available on github, as is this wiki with the API reference and Getting Started guide. Examples are available on the Polychart.js website. As always, please email us if you have any questions and we would love to see the charts you've built!