Tracking should be accompanied with timestamps

One of the important details of tracking someone is that the longer you have been doing so, the more meaningful it is. As such, I think a time stamp should be recorded (and displayed) showing how long tracking has been on going.

If you are looking at the profile of Bob, who is new to you, it'd be nice if you could see that people you are tracking are in turn tracking Bob and have been for a long time. This will help give more weight to their tracking (opposed to if they only just start tracking Bob).

Equally, when looking at your own profile at who you track, it'd be nice if you could see how long the profiles have been tracked for, both by yourself and by others. It could be the date of earliest tracking from people you directly track, or maybe globally.

It might also be nice to see if you could see a timeline of every time a profile was tracked. If I am not mistaken, seeing a steady stream of new people tracking, or even a burst earlier on, helps corroborate that this profile is 'legit'.

No files, tests, or entry points are named. First clarify whether the goal is tracking duration, earliest tracking dates, a full tracking timeline, or all three; done would require an agreed scope and visible timestamps.

Written by the indexing model from the issue text.