What's the difference between shadows and shaders?
Shaders are a technique for telling the GPU how to draw stuff.
Shadows are... shadows, they make stuff that lights don't shine on darker.
You can use shaders to implement shadows (but it is possible to implement shadows without shaders).
If you've noticed the specular on the blocks, that is an example of a non-shadow shader effect.
I'm sure in time we'll add a lot more neat stuff. Right now we just want to get shadows solid and ship an update that works for everyone!