Last modified: 2011-03-13 18:04:33 UTC
The relevant discussion is at the attached URL. The idea was to allow ''at least'' certain variables, such as CURRENTYEAR, CURRENTMONTH, and CURRENTDAY2 to be used with subst in user signatures. A very useful application would be a signature of the form: [[{{subst:CURRENTYEAR}}-{{subst:CURRENTMONTH}}-{{subst:CURRENTDAY2}}]] which would allow timestamps in signatures to be localized according to user preferences. While I'm not positive that this is currently impossible, I did test it on my own account at the en WP, and the templates subst directives were left unparsed.
We deleberetly use the default option of the content language rather than the user preference as the date format to maintain a uniform look.
This could be useful for templates where people want to show the time it was added (I'm thinking about http://en.wikipedia.org/wiki/Template:No_source).
Although I voted for this bug, I should point out that at [[m:Help:Template#subst]], it is indicated that the subst function is not suitable for a timestamp.