What is Steampunk?

Many people ask "What is Steampunk?"  They have never heard of it which is partly why it is only a niche, and not a larger market.  It is also why it has grown with the explosion of the internet and social networking.  Steampunk is a psuedo time period that copies the feel of London Victoria, but combines unnatural or science fiction-like elements to that time span.  An example is the book by Naomi Novik, Blackpowder War, or the gritty science fictions of China Mieville.  Imagine wood and brass, black powder musket rifles, and funny accents.  But the video below can explain it better than I can.