Hi, I didn’t understand for what reason Mike used vertex groups in the lamp animation, What is special about it?
Thanks
Shira
It’s for me too long ago, when I did these lessons.
But creating vertex groups are very handy in some situations.
Your model can be seen due to the fact that you have created faces. A face is defined by at least three vertices. Blender only works with vertices, not faces. A face is just a result of a set of vertices.
You can also name a group of vertices (faces). This group can be used to add material to. Or manipulated only those vertices in the group. Use this group to mask option in blender. It has many, many usages.
But unfortunately I can not tell you, in this particular case, why Michael use a vertex group.
maybe someone else?
Watching it, and the next one, it seems to be the later binding of the armature to vertex groups. Being as he joins all the lamp into one object.
Besides just knowing about vertex groups than can help you in other situation in selecting parts of a model mesh.
Ok, but in this case he chose all vertices of 3 models mesh… so I don’t understand the difference from parenting all these models to the bone
anyway I’m curious to try some animation selecting by this method only part of the mesh…
Thanks 
Normally you would use weight painting to connect a mesh to a bone.
But that is a different way to do it and need more explanation.
I think that why he uses this simple way of doing things.
Now all vertices are 100% connected to the bone.
With weight paint it’s a value between 0 … 100% (more mesh control)