If you want to get more people playing TERA, then go and figure out why most people aren't playing it, hone your game development and leadership skills, move to Korea and learn the language, get a job at Bluehole Studio(hopefully in a decently high position), improve whatever part of the game turned people off and then find a way to regain the industry's faith in the game so they'll try it again.
Putting ads up for a game that everyone's already played is a surprisingly bad way to make a game more popular.
