People have a built-in need to capture and depict their experiences, and that's probably been true for centuries. Millenia. Human history has left us with cave paintings of surprising creativity, detail, and craft that rival modern visual artists, dating from 30,000 or more years ago.
We seem to have a need to depict our experiences and weave a narrative about what happens in our lives–through books, video, paintings, stories, drawings, and yes, probably shared tracking devices like fancy body cameras that capture our adventures around the world. Like the ancients these actions earn us, perhaps cheaply at times these days, a small piece of immortality.
Storytelling, before alphabets and the written word came along, provided an oral history that could be passed along the generations. It let people depict the narrative of their otherwise short and amorphous lives–it permitted them to talk to the future, before they vanished forever. Maybe that's what we do too, when we share a year's worth of images that show us rambling over a distant landscape. Maybe that's why you and me take pictures and write books and blogs and fitness diaries.
My young son listens to audio tapes of and retells the stories in the Iliad and the Odyssey. To use a pop culture reference, in the movie Troy, a boy has to fetch Achilles, brooding in his tent, to fight a rival warrior in order to decide the outcome of a battle. The boy tells the reluctant Achilles "He's the biggest man I've ever seen–I wouldn't fight him..."
Achilles, played by Brad Pitt, defiantly replies, "That's why no one will remember your name." He was already by necessity (because of their short and provisional lives) thinking about his legacy. Now he's psyched to fight.
I found the movie 127 Hours very compelling, partly because it was a film about a man filming his own ordeal in a Utah canyon.