I don't know. Katya pimps nail polish, and Adam pushes pastries disguised as tales of street meetings with prominent leaders. Either that or I'm getting the wrong message from brexitcast.
In all seriousness though. You've described excellent examples of what I was trying to get at: it isn't always obvious where to draw the line; useful promotions, acceptable [to the listener] ads, and the point where it becomes just too much.