there seems to be some problem with the lighting. Actually it is not a problem, just something that would add immensely to the realism. If you do per vertex normals, rather than face normals, then you will get smooth lighting across the face.
I suppose I should provide code rather than just suggestions.
First Impression: Extremely simple and not very polished app compared to other WebGL demos such as the Quake 3 BSP app at http://media.tojicode.com/q3bsp/
The raindrops are great, but it was the greeting in your source code for aerotwist.com that made me roll off the chair. Love the aerotwist logo in underscores and pipes.
I suppose I should provide code rather than just suggestions.