That usage sense is called a discourse particle: http://en.wikipedia.org/wiki/Like#As_a_discourse_particle.2C_filler.2C_hedge.2C_or_speech_disfluency http://en.

That usage sense is called a discourse particle: http://en.wikipedia.org/wiki/Like#As_a_discourse_particle.2C_filler.2C_hedge.2C_or_speech_disfluency http://en.wikipedia.org/wiki/Like#As_a_discourse_particle.2C... It can contain signal when used as a hedge ("The restaurant is only, like, five miles from here.") but generally that usage just substitutes for 'uh' or 'um' while signaling some group-membership (originally Valley Girl I think?)