I was thinking a webring like solution would allow discoverability while still owning your platform. Discoverability is a major concern I've heard from many bloggists.
You could have a footer that is some simple js that allows you to go to a sampling of related articles. Could track cross-domain referrals and give them a cut of generated ad revenue (not sure how you'd track that just yet).
To keep some of the riffraff out, you can charge a small fee to join the webring. Have the rings be able to manage their members to facilitate the removal of junk links.
Might make a nice small saas; though I'm not sure what the price point would be to make sense. Each ring priced as low as a $1/mo? $5/yr? Maybe a popular ring is worth $1000/mo.