I've noticed something recently on this site. It's a weird thing, but it appears to be becoming common. Answers are seen as only being reliable if they have a source.
This isn't the case where someone points out an answer is wrong by pointing to a reference, but rather declaring that an answer needs external verification.
Imagine such a thing on StackOverflow.
Q: How do I fix this code
A: Do this. It will work
Comment: DOWNVOTED! Cite your source!
I've seen answers on History stack be declared
Good answer, but would be an excellent one with sources.
This makes sense. This isn't someone attacking the answer, but rather being supportive of the answer. Sources for history are more important, as much of the interpretation of history is subjective.
Is it becoming site policy that answers have a URL attached to them to be considered valid? If so, I'll spend my time elsewhere.