It's the media folks,     Bitcoin shows that positive media coverage is one of the main factors driving the price.
This was most apparent in the early days of Bitcoin, when mainstream press started to report on the new currency and caused a number of short price spikes and collapses. As media coverage increases and other factors are brought in, it is harder to distill the effect of the media alone. Something similar happens when high-profile companies go public, as investors “pile in” and the value rapidly increases from a low base. Think of a company like Twitter, which saw a huge sharemarket “pop” when it went public.