I think it makes the most sense to put tokens as a separate layer on top of the raw storage/communication layer. (If I understand correctly, this is what Fileco

I think it makes the most sense to put tokens as a separate layer on top of the raw storage/communication layer. (If I understand correctly, this is what Filecoin is intended to do.) The same content may be stored and served by both donated and charged-for nodes cooperating. For example, imagine someone has a blog, for which they've paid the network some number of tokens to host. I find one of their articles to be particularly useful, so I pin it on my own node (perhaps with a bandwidth limit if I don't want to get flooded should it become popular) and thus donate a small amount of hosting to the owner of the blog.