I am discovering for myself the world of RSS, ATOM, and blog feed aggregators. I tried to find out what’s the difference between RSS and ATOM (here is a good starting point), and it looks like one of the differences is in the date format.
The older date format is RFC-822. It was adopted in 1982 and it has only two digits for the year part. Indeed, in 1982 the 21st century seemed like a very distant future. I do remember that feeling
The newer date format is RFC-3399, that was adopted as late as 2002. It specifies for digits for the year and reinforces the mandatory specification of the time zone, although many existing applications don’t do it. This is how the RFC authors justify their decision:
Since interpretation of an unqualified local time zone will fail in approximately 23/24 of the globe, the interoperability problems of unqualified local time are deemed unacceptable for the Internet.
In other words, gentlemen, wherever you live, keep in mind that you are not the center of the Universe. Approximately 23/24 of the globe has different local time! If you forget this, your interoperability will suffer. Be humble and specify your time zone.