See also T94353: It is impossible to copy the timestamps of Flow comments

@Nemo_bis: do you mean this should not even be implemented as an option? It should be the default and only behaviour?

Alternatively, we could Either:

• show the Elapsed for a period of time, and then switch to Exact
• show both at once (for a limited time), as gmail does, and described in T94353#1178467 -- (this is my recommended option)

fwiw, I did some quick research into what other sites use:

Exact timestamp only:

• Classic Email.
• Lifehacker: http://twocents.lifehacker.com/the-salary-required-to-be-middle-class-in-every-state-1695393156 (but Elapsed for 24 hours on mainpage)
• The Verge: http://www.theverge.com/2015/3/31/8316775/amazon-dash-buttons-turn-homes-into-shopping-carts
• Tumblr: http://mikerugnetta.tumblr.com/
• Livejournal: https://suricattus.livejournal.com/1874113.html
• Phabricator

Elapsed timestamp only:

• Youtube: https://www.youtube.com/watch?v=iVvRWVoHDb8
• Reddit: https://www.reddit.com/r/test/comments/1mo1jj/testing_comment_depth/ccazy0e

Mixture:

• Gmail: (Exact, followed by Elapsed in brackets for 2 weeks)
• BBC News: (Elapsed for 12hours (?) then Exact) http://www.bbc.com/news/world/us_and_canada
• Twitter: (Elapsed for 24hours, then Exact) https://twitter.com/Wikipedia
• Facebook: (Elapsed for 24 hours, then "yesterday at [time]", then Exact).
• Stackexchange: (Elapsed for 2 days, then Exact)): https://english.stackexchange.com/questions/182490/what-do-you-call-someone-who-believes-in-ghosts
• Discourse: (Elapsed for 1 week, then Exact) http://try.discourse.org/t/whats-your-all-time-favorite-movie-scene/264
• Quora: (Elapsed for 1 week, then Exact): https://www.quora.com/Meerkat-app-2/How-expensive-is-massive-live-streaming-video-nowadays-and-what-is-the-effect-on-Meerkat-now-that-traffic-seems-to-be-exploding vs https://www.quora.com/Is-Trevor-Noah-really-the-best-person-to-host-The-Daily-Show
• Trello: (Exact, although it uses "Today" and "Yesterday" instead of the date) https://trello.com/c/FeEYcx2f/674-fundraising-monthly-recurring-questions

Nothing:

• Medium: (no timestamps for comments) https://medium.com/about/why-medium-notes-are-different-and-how-to-use-them-well-5972c72b18f2

In T94648#1178600, @He7d3r wrote:

@Nemo_bis: do you mean this should not even be implemented as an option? It should be the default and only behaviour?

No, I just think it's worth tracking what preferences are being added or removed.

But that was only for preferences which should be removed (from MediaWiki), not added (to an extension)...

Why a user preference? We're trying to avoid those.

I've clarified the title and description, to indicate that a "user preference" is now just an alternative option
What seems to be recommended now (both internally from discussions, and externally by practices at other major websites that have timestamps as an important component - see my long list above), is to show either

• a combination (e.g. like gmail, showing Mar 22 (12 days ago) for anything up to 2 weeks old)
• a mixture (switching from Elapsed to Exact after 12 or 24 hours),
• or to always show Exact timestamps by default, with Elapsed times given in a mouseover tooltip. (not as a text-flip as is currently used, because that makes it hard to copy&paste the exact timestamp. (this is a common practice on some wikis, especially when communicating within discussions - e.g. "In your comment above from 16:11, 4 October 2013, you suggested that [...]")

Copy from merged task:

In T129610#2111230, @Pginer-WMF wrote:

Some considerations (some I mentioned when discussing it for Flow in T111596#1804185 ):

• I totally agree with relative timestamps being useful in the "recent period". So keeping relative for a short term and absolute for a longer term makes total sense to me.
• I also proposed to make the absolute times to be contextual, that is, not repeating the year if it is the current one. That helps these to be more compact but still read naturally.
• In the specific case of notifications, absolute timestamps may just need the day reference and not the exact time. If we are using "2 days ago" for a recent notification I don't think we need to know that last years notification happened at 3:15pm, knowing that it was on "April 3, 2015" should be enough.

I would propose the "recent period" to be the current month. So an example list of timestamps could be:

• 3 min.
• 2 h
• 1 day
• 20 days
• Feb 1
• Nov 20, 2015

This keeps things consistent with the division by day we use in the Notification Page (i.e., you don't have several daily groups with notifications saying "1 month ago")

More timestamp format related discussions at T94648: Examine the use of Elapsed vs Exact timestamps in Flow