If we only allowed unpaid editing, then disclosure would be driven underground. I do not think WP:COI precludes editing on topics you created, or [[user:Ken_Birman]] would've been blocked a long time ago, and I would really hate to discover that he went for sock puppets. I would *rather* discover that he paid one of his students to link-fill one if his articles on [[gossip protcol]] (currently with a definition far too loose for use) or [[virtual synchrony]] (needs to be contrasted with asynchrony). A lot of other business models feature wikipedia as a resource, and I do not think it is in our interests to make them hide. It is enough that we hav a WP:COI.