Bedpost
In addition to data that accumulates automatically as you move through the online and physical world, intentionally gathered data allows users to look back over space and time to work with personal information visualizations. Nick Felton asks people around him to help him gather data about his movements. The site Bedpost allows you to track statistics about your own sexual activity.
(My partner says I must point out that the Bedpost screenshot above is by someone named "activekev" and is in no way affiliated with the author of this article.)