If you want to remove the merger/dilution from the analysis, then you would say the March peak was the 'Ides of March' when the market was expecting the release of BitAssets, followed by a loss of interest in the waiting period. The August peak was the release of BitAssets and interest stayed fairly strong with the December peak being the market anticipating some sort of 1.0/SuperDAC release followed by a loss of interest during the waiting period.
As we get closer to 1.0, Moonstone and other tangible developments, interest may pick up again & the chart you linked to does seem to show a slight up-tick in April.