bitcoin is a online currency & its peer to peer system. bitcoin popularity growing day by day,that's why its price also growing.I think after end of the year bitcoin price going to be very high.
After what year? 2018? I dont think so, to be honest. Last year the hype was over the sky, mining become so popular that reached out to every person with a little knowledge of browsing the internet. My opinion, btc price will remain as this for little longer.