I think it will always be a niece market to some extent. It's never going to become a mainstream payment method for Joe Public. However, there's still massive opportunity for increased adoption. Right now Bitcoin really is a geeky thing. Nobody outside techie circles has heard of it. It's slowly starting to permeate the mainstream financial news and as press coverage increases, we can expect much more growth as investors with a penchant for high risk / high gain investments put their money into it.