I have had similar experiences since: finding again an entry left some years earlier in the visitors' book of a church or bothy; having returned to me pieces of schoolwork written when I was very young.
All my life I have made marks; traced my name in sand and snow, etched my initials in tree bark and school desks, painted rooms, planted out gardens, written all manner of things. Most of my marks will have been erased by time and tide, most are forgotten and certainly never to be stumbled upon again. But not all. There will be little scratchings here and there; evidence of the passing through by another, younger me.
Several of my friends have recently started or re-started writing blogs, newcomers like me. They have been posing questions: Why am I writing this? For whom? What do I hope for? My answer is simple. I am making marks, just as I have always done. Somewhere out there, a traveller may pass by and say 'oh look, someone has been this way before.' The traveller may even be me. Another me, older and on the homeward leg.