Nook is an RSS reader for Mac and iPhone. It keeps what you subscribe to on your own device, so it opens instantly and works on a plane.
Articles are downloaded and stored locally. No account is needed to read, and nothing stops working when the network does.
You see what you subscribed to, in the order it was published. There is no ranking, no recommendation, and no advertising.
Subscriptions import and export as OPML. Nothing is locked in, and no part of reading depends on a server Nook runs.
Nook Plus is an optional feature for people who also publish. It gives you a small website with an RSS feed, and stores what you write in a personal repository that belongs to you rather than in Nook’s database.
Nook is in development. It is not yet on the App Store, and publishing is limited to invited writers while the service is being proved out.