In my opinion, it's a combination of spam attacks (with the goal to lower the price and generate panic in a context of high volatility) and real transaction volume growth, not only by new users but also by users that move Bitcoins to and from exchanges to profit from the price growth.
The more good news about Bitcoin such as AU and Japan has pushed the new adoption for bitcoin in his environment.
Spam and mass adoption That can make the bitcoin network will run on high traffic.
It looks bitcoin network will have exploded as soon as possible.
We need the block increase to support mass adoption