The website futureme.org, created in 2002 by 'Matt' and 'Jay' is based on the principle that memories are less accurate than emails. It is basically a time capsule service. You send an email to yourself and you get in back in a time period you decide, typically a year. It can be used as a bullshit list of things you did in a day, or a retrospective look into how you existed in the past, and through comparison - a look into how you have changed, goals, trials, tribulations, even personality and behavior changes - a concept that has captivated psychologists for years.
It can even be used as an emotional vent - its not like writing to the same person because odds are that the person you have written to has changed beyond recognition.
This all only applies if you can brave the past though.