Are virtual reality massive multi-player games, like sword art online, really possible?

Are Virtual Reality Massive Multi-Player Games, Like Sword Art Online, Really Possible?

In the Anime Sword Art Online the players used a device called a nerve gear to play the game. The nerve gear puts the player into a virtual world that they become trapped in within the game until the game is finished. I loved this anime but the part that interested me the most was…