[[creative commons licenses]] ShareAlike inhibits even the same author posting it under NC (commercial rights reserved) without major changes, and only to the degree that sharing will make promotional efforts go into a hole. NoDerivatives and ShareAlike definitely conflict, because NoDerivatives inhibits development, while ShareAlike is meant to encourage it. CreativeCommons-ByAttribution-NC-ND is very much like "All Rights Reserved", with your rights spelt out in abbreviations, which are a no-no the first time you use them in a document. (I am blocked. Feel free to use.)
There is an immense degree of tolerance for linking, even to commercial sites, just because financial services let you back out of deals and there is always that warning arrow saying "This link heads off site, so talk to THEM before you bother us about content problems". Anything that can get out of control on wikipedia will get out of control, so there are lists of documents on wikipedia with too many external links.
I recently spelt out both restrictions and ballpark figures, complete with Paypal code and a degree of tolerance on my fractal gallery. _______ <a href="http://freenet.edmonton.ab.ca/~brewhaha/">BrewJay's Babble Bin</a> SherLok Merfy's Moranda: Anything you say or do wrong can and probably will be used against you somehow, especially if you are caught.