So, there is this little question. Answer to it is here on Drupal.org. This post is to short to make any excerpt from it, and copying it whole might be a copyright violation. Rewording it to obscure it's origin doesn't seems right either. So what's the best - fair and legal - way to provide an answer?
As far as I can see, the documentation can be used under Creative Commons License, Attribution-ShareAlike 2.0, with PHP code under GNU General License 2.0, while posts on Stack Exchange are under Creative Commons License, Attribution-ShareAlike 3.0.
That is for the documentation; nothing is said for the forums.
As far as I can understand there isn't any copyright problem; as long as you give attribution to where you find the answer, there should not be any problem with reporting what you found in Drupal forum. Keep in mind that it is generally possible to expand the answer with something you personally write, and use the answer found on Drupal.org forum as guide.
As per code licensed under GPL, you can always show a quote of that code on Stack Exchange, as that falls under fair use. For what I understood, that includes also quoting a full Drupal function, since a single Drupal function is not the full Drupal code.