You could look it up and see for yourself. It's applicable to all sorts of collections such as map data and I'd presume also a book database but IANAL so best if you see for yourself - my intention was just to point out (what I hope is) the applicable legal principle for anyone curious about this
I don't know about that ... HN is a conversation. It's not a very interesting conversation when you say a few words and then refuse to say more, telling the other people at the table to look it up.
I could look up lots and lots of things to see for myself. I wouldn't be reading your comment, and there is not enough time in the universe. Readers don't have time to look up everything other people post. It's up to the commenter, I think, to say what they intend and what's valuable about it.
Fair enough. Not everyone always has time to reiterate Wikipedia on what seems to me a relatively well-known concept, at least among people to whom this is relevant (e.g. me as an OpenStreetMap contributor, database copyright is like the first thing you learn after making your first edit because that's why you can't copy data from just any source). There's always a lucky ten thousand around I suppose :). Maybe I should have at least cited something