At a minimum what should as the authors of the posts here to be sure we are properly attributing external content?
We should be:
Linking to the original source: A hyper link would direct users to the original content. A book can just be link to excerpt of pages (some books are posted online) or online store that sells it.
Use block quotes >
to indicate when words are not your own: In addition to the links
Basic example could be like:
Consider a quote from Jane Austen's: Pride and Prejudice
It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife.
Excerpt from Project Gutenberg
The markup for what is above is:
Consider a quote from Jane Austen's: Pride and Prejudice
>It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife.
<sup>Excerpt from [Project Gutenberg](https://www.gutenberg.org/files/1342/1342-h/1342-h.htm#link2HCH0001)</sup>
It does not have to be perfect and formal nor am I trying to set a standard. Just enough so that readers know where the words came from and how to get to it themselves.
Proper Attribution is important and we should strive to give credit where credit is due. In some cases you need to be careful of any licensing restrictions for reposting content as well. In the case of the snippet I have above I can post it because of the first paragraph on the linked page:
This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever.