Here's how CNN describes the site:
The ECOSPHERE is a real-time Twitter Visualiser that aggregates tweets tagged with #COP17 and then orders them into specific topics or discussions.
Each submitted tweet will stimulate growth in the individual topic plants causing some plants to grow larger or faster than others depending on how the conversation is evolving. The result is an instant snapshot of how the world sees climate change.
And here's a screenshot:
Each colored cauliflower-like growth corresponds to a specific topic, and expands or contracts under a combination of tweet and time pressure.
Not just WebGL, but WebGL linked with Twitter to visualize data in a way that smacks iconically of the data itself. Runs very smoothly in my browser, too.