--breaking down the definitions--
NOOB: a newcomer or novice, esp. an inexperienced user of the Internet or of computers in general.
SKATES: Shoes or light boots with a metal runner or blade fitted to the sole, used for skating on ice.
EXPLANATION: although the definition of a "noob" and a "noobskates" (when referring to a person) are virtually the same, the use of "skates" on the end of "noob" reinforces the absurdity of the individual's "newbieness". It is both singular and plural with the s termination.
"Damn, that guy is a real noobskates."
"NSA is the biggest noobskates I have ever met."