Now I see the thread over on Rock em & Roll Em. This issue is trickier, because posts on boards are not easy to compare, sometimes are written in a less than clear way, sometimes by people not used to sharing credit, and may disappear after a while. Scientific papers, on the other hand, have to get past reviewers, and typically have dozens of references, and are permanently archived when done.

People just have to do their best to be upfront about their sources, and it's good to establish favorable reputations by mind mannered and generous behavior.