[andai]

I have updated my opinion accordingly: I agree that in the case of actually timeless content, hiding the date benefits both the reader (who would otherwise discount the information) and the author (whose work would otherwise be perceived as less valuable than it actually is).

It doesn't matter if Marcus Aurelius wrote his Mediations in the 160s or 170s (or the 1700s for that matter) as they truly are timeless!

However, I've run into articles that were very much not timeless, e.g. technical tutorials which were hopelessly out of date, with no indication that this was the case (since they hid the date). In such cases, hiding the date benefits neither reader nor author.

Presumably you did not mean that date-hiding should be implemented universally. I'm just sharing those experiences, which led me to associate missing dates in articles with confusion and frustration -- since those are the only ones that elicited a strong response: when I needed it, and when it wasn't there! The cases when the date didn't matter, but was there, left no lasting impression.