Stands for: "I know the hits" fan. One who claims to be a fan of a band, but who only knows the hits. Sometimes people pretend to like a band to impress another, coming off as being an IKTH fan.
Tina: Rob is only an IKTH fan.
Tim: How do you know?
Tina: He claims to love Alice in Chains, but only talks about Heaven Beside You and Man In The Box.
Tim: Damn, what an IKTH fan.