Lyric discussion by fromadistantsun 

Cover art for Say Something lyrics by Something For Kate

It's probably about a more generalized lack of communication among people, like other comments here have said, but personally I associate it with the frustration of trying to communicate with someone you care about when they're shutting you out.

There's such a sense of restrained passion in the lyrics, the idea that the connection between these people is incredibly volatile ("if we met we would exhaust this place"), but it's being stifled by the other person's refusal to communicate. Having been there, I entirely understand the desperation to hear them just... say something, anything, to end the "days and weeks" of cold silence, to make that "breakthrough" and feel something again. Incredible song.