"I can sue them to get paid for making money on my work without my permission and without offering me a cut", or can it mean also "I can sue them for just using my work without permission"?

You're referring to the definition of "publication" in the US copyright statutes, correct? Does displaying a work for zero consideration comprise publication? What if the work itself relies on quotations attributed to others / logs lifted from a "commercial" forum without those Copyright Holders' permission? ;-)

IMHO the best policy is that you cannot operate in secrecy in 2007 if you've used the Send button- or probably at all if you've let the information out of your sight. This isn't particularly new: Benjamin Franklin once said that "three may keep a secret if two of them are dead." ;-) Even if you can assert Copyright after the event, that's an "own goal" if the information you're trying to keep secret becomes the primary exhibit.