In self-Knowledge through numbers I took a very brief look at what is known as "lifelogging" or the attempt to capture e everything we do and see. Here is a "constructive" critique of this idea. I can only agree with one of their conclusions: "Selectivity, not total capture [should be the aim]. Rather than unfocused efforts to "capture everything," system designers should channel their efforts more fruitfully by identifying the situations where human memory is poor or targeting the things users most want to remember. These situations are where the systems would provide their greatest utility. Furthermore, people may sometimes want to forget, a view anathema to the lifelogging philosophy."
As Friedrich Nietzsche already pointed out, forgetting is just as important as remembering, and taking note of something is no more active than trying to forget it: "Forgetting is not simply a kind of inertia, as superficial minds tend to believe, but rather the active faculty to ... provide some silence, a 'clean slate' for the unconscious, to make place for the new... those are the uses for what I have called an active forgetting ..."
Whether some of the more extravagant conclusions Nietzsche draws from this are true or or not is one thing, it is quite another to acknowledge that good note-taking always involves actively taking note of some things while actively forgetting others.