Maybe. But we use "last updated" as a useful signal in many, many places, across code, documents and books, and entertainment. We like recent, new, updated st

Maybe. But we use "last updated" as a useful signal in many, many places, across code, documents and books, and entertainment. We like recent, new, updated stuff, and we like "authentically old" stuff. As a signal, the date provides value. Having it as "copyright" or simply "last updated" has similar impact in this case. Sure, no one in the US __needs__ to do this, and there is a cost to it. But the benefit of the signal could outweigh. Having no date or an old date may send the signal that "the dev team has good legal support", but I wonder how common that perception is. We see from the comments and the parent post that at least the HN crowd has a good chunk of folks who didn't know that date isn't needed. It's an empirical question to test: does date presence affect evaluation of the object? It would be fun to see. (I would want to try "no date", "last year", "3 years ago", "current year" to see if user perception of the object changes based on presence and time passed).