It is assumed that, unless otherwise noted, the person adding a bit of text is its author.
By posting stuff you give us permission to display it, and maybe even reprint it.
We assume you don't own any images you post. We're mostly okay with that. Please try to properly attribute.
Don't go posting the entire text of things. If Neil wanted the entire text to be online he would have put it online somewhere; find and link to it.
In some cases certain works, such as academic papers, have already been posted online with the author's permission. We are hoping this qualifies as putting them out in the public domain because we plan to snag copies whenever we come across them and upload them here for safe, centrally-located keeping. If you are the author of a work posted here and you wish it removed utterly and completely, email DanGuy.