VimArea is a vim implementation over a textarea. There's a plenty of online Vim out there with different degree of impl and approach.
This one is none the other, the goal of this implementation is to minimize the footprint for creating additional iframe or divs.
This is not a traditional vim ( yet ). I recommend to use wasavi if you can. It is a more mature project. Even if this project is finished, it would not provide the functionality like wasavi does ( mostly because of the limitation of a textarea ).