I've been thinking about that as well.

On the surface the I is whoever is doing the talking or saying the "mantra." The You would then be whomever they are addressing. (A person, a place, a feeling, God)

After a while it occurred to me that the I and the You are interchangeable. If you let the idea sink in, it erases those boundaries and leaves you in a state of oneness with yourself... the so-called "other." You is anything that you haven't assimilated into I yet.

At least that is how it feels to me.

=)