This came to mind after seeing this question: Why is Ulquiorra the only espada with a second release?
While I have no problem with speculations as answers, since I sometimes give them, I agree with what a post discussed that even speculations require support via facts or any information that is canon. Topics regarding references have been asked before, here and here, to name a few. However, I'm not sure if I can agree to what was said in here. To quote:
There's nothing wrong with referencing any source you may find, and think that is credible. Whether you, the OP, accepts it as one, is your business.
If I understand correctly, this would mean that any source is valid as long as the OP and the one who answered think it is credible. While the question might be asked for the OP's benefit, the problem is that the post is public. People come to the site seeking information, and the site is a Q&A site relying on facts which differs from other sites. There could be a spread of misinformation if one just uses any references he/she can get a hand on as long as he/she 'thinks' it is valid.
The question regarding Ulquiorra was answered using information from a Tumblr and Yahoo! Answers post, which also only state speculations without information referenced/cited from canon to substantiate the claims. Despite this, it was accepted by the OP.
So, what sources/references should we consider as valid/acceptable? Or do we only give the discretion to the OP and the 'answerers' as long as they include a reference, as stated in the meta post cited above, and as long as the OP thinks it helped him/her?