Phase One: The earliest of early adopters increase their bitcoin holdings by mining and trading with each other.
Phase Two: The newest wave of adoption comes from technical minded people using specific exchanges and person-to-person trading.
Phase Three: This wave of adoption has reduced any complexity for investment by having more exchanges, in addition to ATMs and other financial vehicles to get into Bitcoin.
Phase Four: The greater public become exposed to Bitcoin, and it starts to erode conventional Finance firms margins. This is also going to be the part where grabbing-at-straws regulation will come down, in addition to various PR smear campaigns that appeal to nationalist tendencies and appeal to authority trying to stem the tide.
Phase Five: The anti-Bitcoin propoganda has largely failed, and as successive generations of people become used to using Bitcoin, the Financial industry firms that have failed to adapt erode and wither away, as well as nation-states that refuse to integrate into the new global economy.
Phase Three baby!