Previous Twitch competitor (Owned3D) was successful in gaining viewership by poaching streamers from twitch with better deals.It seems like it was pretty easy for personalities to transfer their fan bases over. Many twitch streamers already post highlights of their streams to youtube so they've already established a presence there. I would also think that youtube will be better at serving video advertisements and handling copyrighted materials on stream (currently twitch handles copyrighted music by muting archived videos that contain it, whereas youtube places an advertisement for the song at the bottom of the video).