Hmmm. The closest I can find is "If people are expected to behave well, they tend to; and vice versa."[1] There's nothing in the guidelines that's even similar,

Hmmm. The closest I can find is "If people are expected to behave well, they tend to; and vice versa."[1] There's nothing in the guidelines that's even similar, except for avoiding comments with no substance. I suppose that, as long as you're civil about it, there's no need to do anything that the community expects. However, this was exactly my point; being called out to provide a citation and actually responding to the request (as opposed to saying "No, this is not an academic paper. But I distinctly recall ...") tends to lead to changing the views of at least one person in the conversation. The last time I was called upon to provide a citation, I wasn't able to find a credible one, and adjusted my beliefs appropriately; therefor, I'm of the opinion that refusing to provide a citation is evidence that you know that you're wrong (or, occasionally, that a single search would find the citation; that isn't the case here, I tried. Almost all of the results involve how Gmail was seen as a huge advance for having simple text ads which were relevant to the content of emails they were displayed next to). [1] http://www.paulgraham.com/hackernews.html http://www.paulgraham.com/hackernews.html