Writing for pay
Things that should be obvious but escape some people...
If you write about a subject that is paying you, and don't disclose that in your writing, it's not honest.
Jeff Hess is a source for this and always many other tasty tidbits of info.
Disclosures: No one pays me to write this blog. We have no ads, although you could argue that linking to my wife's Jewelry Site and my sister's Chapbook sites are kind of ads, but they don't pay me for them either. At least the links don't feature animated gifs or windows that can't be closed whilst blinking at you.