Gone doesn't always mean death, either. I have friends that I no longer speak to (for no reason other than drift, I guess) or have fallen out of contact with, and I still think of them often.

I'm certain they're probably still alive, but I can't help but wonder, who am I gone from, and do they miss me? I wouldn't even know unless they said something or told me.

That's why its always so important to tell people how you really feel. That's something I am becoming more and more comfortable with as I age and mature.