I'm working on a website on which users should get an overview on which dates they executed an action. For example, user X executed action Y on Aug 21, Aug 28, and Sep 12. What would be a good and user-friendly way to display this information? Of course, a simple list would do the job but are there maybe any better solutions?
NHSDigital, the organisation behind the UK's digital healthcare, has some specifications on how a date should be displayed to the end user, mainly for the purposes of being user-friendly and unambiguous. These are good guidelines to work for even outside of healthcare and outside the UK for this very purpose, and have had a lot of research behind the decisions in them.
The recommended way to display a date is to spell out the name of the month and use 4 numerals for the year instead of just 2, for example:
23 September 2016
There are multiple things to consider when displaying a date in just numerals as pointed out in this document, such as how date formats rely on the user's locale.
“Visitors to a web site from varying locales may be confused by date formats. The format MM/DD/YY is unique to the United States. Most of Europe uses DD/MM/YY. Japan uses YY/MM/DD. The separators may be slashes, dashes or periods. Some locales print leading zeroes, others suppress them. If a native Japanese speaker is reading a US English web page from a web site in Germany that contains the date 03/04/02 how do they interpret it?”
Another multilingual and numerical-only format to consider, although less readable for just display, is ISO 8601 which suggests to format dates as YYYY/MM/DD:
For activity streams, it is an user-friendly way to show relative timestamps. You can show temporal information by "user X executed action Y [right now|one hour ago|yesterday|a week ago...]" relating to the actual time.
You have to check if it fits to your requirements, but in the way you want to use relative timestamps, give the user the opportunity to get the absolute timestamp and to show it by default on older tasks.
You can find articles to this topics, e.g.: http://uxmovement.com/content/absolute-vs-relative-timestamps-when-to-use-which/