It seems you forgot the third way of acquiring Bitcoin, which involves working for Bitcoin (earning Bitcoin) Because since the investion of Bitcoin in 2009, these has been the three ways of owning a whole or fraction of Bitcoin. Because just like the bitcointalk forum whereby you get to earn a fraction for effectively communicating for it's development, together with exchanges who pays you a commission for promoting an affiliate link and online sites who pays you Bitcoin for writing a blog post (freelancing jobs)