I debated exactly how I wanted to include the last part, about relaying and filtering. Technically it is involved economically, but in an indirect way. The "economic node" thing has been used to argue against filter supporters, and I don't think that's a good argument. However, I decided not to put my opinion about that in my original post. It's actually kind of up to you how you interpret the economic contribution of a node that is only relaying and filtering.