Who are you? Who am I? These are two big questions for your weekend newspaper/coffee combo, but let me assure you ... they seem even bigger at 3am mid-week when you have insomnia and you're sitting on the couch trawling through every Facebook update and photo you've posted.
After becoming the victim this week of a rather unfortunate oversharing/tagging incident, I was forced to reconsider my position on the social network we love to hate.
A bit like Bono, I have found over the years that I can't live with or without Facebook. I've tried both ways with unsatisfying levels of success and vacillated between being a habitual offender of the worst sort of boring status updates to vowing never to make another (until my kitten does something really, REALLY cute that just has to be shared).
As I'm a photographer, Facebook is a dream medium and an invaluable tool for business promotion. As an individual, it is uncharted territory, with minefields of social disaster able to explode without warning.
The tagging this week (which I shall not be going into gory details about) sent me firmly and, I suspect permanently, into the category of Facebook hater.
It also saw me take what I thought were already fairly tight privacy settings to dizzy new heights, resetting the privacy settings on every album and photo to "me only" and starting painstakingly on the process of deleting every status update since I joined waaaaaaay back in 2007.
This requires a commitment which I'm sure Facebook has accurately concluded most people aren't prepared to sign up for.
Since it became possible with a single click to scroll back to any point in a person's Facebook "life", I've tried to ignore that my thoughts on past relationships, events and a really tasty dinner circa 2009 were public fodder for any of my 391 "friends" bored enough to read about them.
In the insidious way of Facebook, it isn't possible to bulk delete past posts and comments. One has to individually go to each entry in turn.
In the dark of night as the world slept peacefully, a battle began between the Goliath of Facebook and one determined little David.
Systematically starting from May 23, 2007, I altered the settings on every post, tag, comment, status and photo until I reached the present and the post that launched a thousand "deletes".
By the time my boyfriend wandered groggily into the living room at 3am and shuffled my weary body back to bed, I was exhausted. But I had won.
What I had also learned over the protracted process is just how much our Facebook history says about who we are.
I like to think of myself as fairly consistent, a personality that ebbs and flows a little like the tide but is essentially the same.
What amazed me, looking back on my views and interests over seven years, is how much I have changed without noticing.
Capricious political outbursts have gradually made way for more measured observations about the world around me, and a timeline once dominated by posts and photos about my all-consuming career have been replaced by pictures showing me smiling and having a life.
In short, I've grown up. Who knew?
Initially resentful of Facebook because I could not delete my personal account without losing my business one, I reconsidered and realised that my (now locked-down) timeline provided a unique roadmap backwards and forwards through time.
Sadly, my new privacy regime means the log for the future may be fairly slim, unless I start secretly posting all sorts of random musings on everything and everyone, then instantly click on "me only".
Which is a move many people ought to consider adopting.