Something that comes up in many sites, but I think will be more common here than most, is attribution. We need to remember (and remind others) to attribute our posts when we source the material online - even if we don't quote it verbatim, and simply summarize, it's right to attribute it.
Not only does this avoid plagiarism or copyright complaints, but it also lends more weight to the post if it is attributed to a reputable source. (Attributing to a magazine might not be as useful as a professional woodworker or carpenter, but it's probably worth more than a random person on the internet, even with a high per-site reputation, right?)
Attribution also helps the original poster and future readers by including additional sources of information that may be helpful in identifying surrounding information, and possibly help them develop their own ability to find answers better.
What guidelines should we follow in attribution?