In my opinion, bitcoin isn't a bubble because last year experts said bitcoin will just pop and will be gone at the end of 2017 but as of today bitcoin is still alive. Why? Because bitcoin is the future, it is where we are going to be. I dont think it will pop and just gone because as long as the community uses it, it will stay alive. As time passes by, there is increasing amount of people who use bitcoin as form of transaction. There are still country who recognize bitcoin as their transaction but it not yet that wide on the country like here in the Philippines. Bitcoin is like a email, as long as the people use it it wont die.