2018? I don't think that we can go mainstream right now because of too much regulations going on around the world. Government as constantly at looking ways for people not to go to crypto so I doubt that it will happen this year. But I believe that we can go mainstream, but not this year though. Maybe it will take another 5 - 10 years before we can see people from all over places using their bitcoin as some mode of online payment or buying stuff in the internet thru bitcoin. Right now its not happening.