Digital audio capture and metadata standards allow individuals to create collect and catalogue recordings of presentations, assignments, lectures, meetings, telephone calls and conversations.
Prior to digital audio capture technology, audio was recorded in analog form using an analog recorder and then converted to digital form. This conversion needed to be done in real time.
Mobile recording devices make it more and more likely that individuals will record greater portions of their personal experience. see:
http://www.itconversations.com/shows/detail375.html
http://en.wikipedia.org/wiki/Sousveillance