data-explorer Some time ago there was a question on meta asking how to check which parts of the day moderators are available on the site. (And the same question might be interesting to know about regular users.)
I suppose that for a user who is active in chat, the graph from the chat profile ia a very reasonable estimate.
It's not difficult to create a graph depending on hour of a day (or hour and day in a week) to show when user made most comments or posts.
