It is not 100% related but I have a premium whiteboard application on Chrome Web Store for $3.99. The volume is relatively small in comparison to folks at Apple App Store, I assume it's because many people barely know about Chrome Web Store yet. My sales figures: http://ohboard.com/blog/10-sales-in-2-weeks/

Though, I suggest you adding your web app to Chrome Web Store since it will not take you more than few hours and it will bring you users straight.