In the comments to one answer here, we discussed whether or not it's should be considered acceptable to, when writing an answer, include a comment about the source of a claim.
My feeling is this - there are numerous misleading and false claims made on the internet (both intentional and unintentional). Treating all sources as equally valid can increase the number of questions that include inaccurate information in them, and makes it more difficult for individuals to answer these questions (since instead of looking into particular facts, people need to figure out from the falsehood what the initial kernel of truth was). If one looks into a claim and finds it to be inaccurate and only appearing on non-mainstream sites, it isn't inappropriate to include a comment about the source in an answer.
Others disagree. So the question is this, is it appropriate to include a comment in your answer about the source of claims made in the question, and if it is, when is it appropriate?
Edit: I generally agree with the views expressed here:
With so much important stuff to talk about, an answer that merely gives shallow >or controversial advice such as "you're using the wrong brace style and >indentation width" is likely to be outcompeted by a more insightful answer.
My advice is, it's fine to offer opinionated advice, but only as an >afterthought following a solidly grounded critique.
