Things like dates, and especially how you can adjust it to match space available, because of cultural norms. If not here, then somewhere need to talk about contextually information, how "Yesterday" is almost always better than "23 October 2010." Relative locations also, and make sure those are just examples, and you need to think about data... Look at TWC data density progression table.
ALSO: Cultural Norms! And just because you are in one country, don't assume everyone is.
Discuss dd-mmm-yy as a good format as it's unambiguous, also. "
Use date as specific examples, but say "there are other types, and maybe special ones for your project. Don't forget to come up with it for these."
- Within the current hour, show as minutes ago. Over 20 minutes, round to the nearest five minutes.
- Within the current day, or within 8 hours, show the time as number of hours ago.
- Within the last two days, shown the day of the week, and the time range, morning, afternoon, evening, night.
- Within the past week, show the day of the week.
- Older than this, but within 12 months, show as Mmm/DD.
- Older than 12 months, show as the year alone.
- 20 minutes ago
- 8 hours ago
- Tues. morning
- Nov 20