Content for the sake of exchanging traffic by means of links. I'm not convinced this is much different (if any different) than what I mentioned. SponsoredReviews focuses on bloggers writing ads for products. Your idea is to have the arrangement be two-way so that both sites write about the other but then you have the issue of all these sites stacking up two-way links which looks like link exchanges. I doubt Google is going to be thrown off by the nofollow links. It's been abused to stop pagerank 'leak' to the point of losing its original meaning. I don't think emphasizing the use of nofollow is going to save anyone from Google realizing sites are putting out farm-style content.