Auren has a provocative post on the digital footprint one creates while communicating:  your blog posts, emails, IMs, etc.  He contends:

Question: with the thousands of
letters he wrote, could we recreate Thomas Jefferson? Maybe.

Now look at
people that blog often and write lots of emails. Could we recreate them? More likely. Especially bloggers like Danah Boyd that
really inject their personality into their blogs. Even more importantly, save your IMs as they
might really reveal your personality.

Some time ago, Baris speculated that one’s financial records also served as an insightful mirror of one’s life.  His point was:

First and foremost, pictures and videos mainly capture notable events, as such they are snapshot of ones life. Your financials capture your routines, what you do over and over again, in a continuous way. It is not the one off events that define you, it is your routines, things you do over and over again. Emails
are good too, but unlike financials that focus on specific events,
email are inefficient since one sends so many of them, hard to get to
the essence of your life through email.

Microsoft
Money would capture, where you worked, how much you made, how your
salary grew over time, when you got a big bonus, what you spent it on,
where you lived, what you did for vacation, where you went on vacation,
what hobbies you spent your money, what school you sent your children
and what activities they did there. Since most transactions you enter in the system has a memo field, you can enter a little blurb about the transaction. So, in my case, every time I go to dinner I write down who I went with. It even keeps track of your social life.

I agree with both Baris and Auren.  However, my nomination for the best representation of who I am and what I think about would be my clickstream.  It’s the idea behind Root.net’s /Vaults.