The original note, as written at the time
TIMESTAMPING KEYBOARD. A virtual keyboard with a specific key for stamping the date and time into a text document or field when it is pressed. Maybe this could be executed by using a gesture.
Ongoing development
A virtual keyboard with a dedicated key that stamps the current date and time into whatever field is focused, executable by a gesture.
It sounds trivial. It is the sort of thing that, once you have it, you cannot work without, and its absence explains a small but real amount of daily friction.
Think about how often a professional writes a date into something: a note, a log, a report, a message about when a thing happened. Every time, they either type it, which is slow and error-prone, or they leave it out, which is how records lose their chronology. The single most important field in any record is when, and we make it the most laborious to produce.
The gesture version is the better design, because it can be used with a real keyboard. Hold the space bar and swipe, and the date lands. That works on a laptop with a physical keyboard, which is where most recording actually happens.
The second reason to want it is discipline. If stamping the time is one gesture, a person will stamp the time. If it is six keystrokes, they will do it for the important thing and not the ordinary thing, and it is the ordinary entries that make a log trustworthy.
Small note on the format, because it decides whether the feature is useful: it must stamp an unambiguous, machine-sortable form. Not “3rd March”. A date that cannot be sorted by a computer is a date that will be retyped by somebody at the end of the year.