User blog comment:SunriseDaisy/The Meaning Behind the Episodes/@comment-3276102-20110510201728

An intervention is an attempt (usually made by close friends or family) to force somebody to face up to the fact that he/she has a serious problem (an addiction, a serious illness, or some such) and needs help.

In ''iStage an Intervention," then, the "I" would refer to Carly, and probably Sam and Freddie as well, trying to break Spencer's addiction to the Pak-Rat game.