I am by no means the expert, but here's what I know. E-ticket night no longer exists. Extra Magic Hours (EMH) were introduced recently, we think, to replace them, and to respond to a program that US has for its on-site guests (front of the line -FOTL). So far, it seems that each of the four parks opens early one day a week and stays open late one evening a week. There is a schedule posted on this site for the EMH through April. You must be a WDW resort guest (I think maybe the Hilton in the Village is also included) to participate. To get in for the AM EMH, you show your resort ID, but for the evening EMH, you have to obtain a wrist band by showing your ID at designated locations within the park. Unlike E-ticket nights, there is no addition charge for EMH.
Please, friends, feel free to correct or add any information. I repeat, I am by no means the expert.