"There are a few places where we run into a morally grey area, specifically when cross-posting. Imagine, if you wrote an article for a news site, and they paid you for it."

Yes, but it's also very common for a publisher to buy limited rights, for instance first electronic rights, and those vary depending on the publisher. Otherwise we'd never get anthologies in science fiction. I agree that disclosure of those terms are important, and the key to avoiding conflict of interest.

In my case, my IGMS columns have a one-year blackout period before I can re-post them. I have so far only posted links back to them, because I want to support the magazine that supports me, and Steemit offers little friction to linking to an outside source. But because IGMS doesn't do much graphically with its website, I could totally see reposting them here (after one year) with linked drawings and photos. It would make no difference to the letter of our agreement, but I would want to add value on the second platform.

http://www.intergalacticmedicineshow.com/cgi-bin/mag.cgi?do=columns&vol=randall_hayes&article=_index