This was a million dollar idea if not literally at least emotionally and creatively. Its a popular site and many of you may already know about it. To me on the times I visit it seems full of heartache and tends to make me melancholy. And it brings home two points; one, that life moves by so quickly and two that you can never really go back, but this site gives it a good attempt.
Here is a link to one I thought full of the elements I mentioned: