Entrance of new people. 2017 has witnessed a lot of new people entering the crypto-world. Not only do these people want to know about bitcoin but are also willing to invest their sums. Even coinbase wrote an article on blog regarding the record increase in number of users of their wallet. Along with this the recent forks cancellations have provided bitcoin more support from people who were earlier in favor of bitcoin fork segwit2x. So cumulative of these factors have made BTC soar quite a bit.