launched its free iPhone app this morning, which introduces Facebook integration, a saved offline reading list that syncs with the iPad app and Instapaper, and new, simple social dynamics of its own. It digests the links shared by Twitter and Facebook contacts, checks for their popularity, and presents a list of the top news stories in a clean, readable environment.

And now, within the network, there is also a menu of simple, text-based reactions: "Ha!" "Wow" "Awesome" "Sad" "Really?" You can also write your own. These reactions have nuanced meanings. They make you think. They also make for interesting ways to browse for stories. It's these kinds of easy, subtle social dynamics that turn basic, single-purpose iPhone apps into paradigm-shifting social networks: think Instagram or Path. has undergone several transformations, from an in-house New York Times experiment to a standalone Flipboard competitor on the iPad. It swooped in to save users of email news digest service Summify, which was bought by Twitter. And now, with a first-rate iPhone app, is really firing on all cylinders.

Personal review time: I have such an established workflow for reading news that I never expect to get much out of a social filtering app like this. I practically never launch Flipboard, for example. I do my best to read my entire Twitter stream, I diligently knock off all my RSS feeds throughout the day, and I save everything to read later in one place (admission: I switched from Instapaper to Readability for iOS when it came out last night).

I didn't use the iPad app, but I liked it. Now that I've had the iPhone version, though, the whole service has worked its way into my day. With the new social dynamics, now allows me to build a small, trusted network of friend-editors from within my social networks.

I follow lots of news people on Twitter, several are on, and I can follow them within the app. Now there's a new layer for commenting on the news in more detail outside of the noisy Twitter and Facebook streams. The app also has a menu for "Reactions" from your network, so I can see only the stories to which my chosen editors reacted.

The synced read later functionality is fantastic, and the fact that it pushes to Instapaper is downright magical. I hope Readability integration is on the way, too, but hey, one thing at a time. My only complaint is that the scrolling is a little bit laggy at the moment, but the interface itself is stark and lovely.'s small team has impressive pedigrees. CTO Michael Young is the former lead technologist at the NY Times R&D lab. Developer Rob Haining also built Epicurious. Designer Justin Van Slembrouck designed the NY Times Times Reader application for the desktop, as well as Wired for iPad.

This monster team is in an enviable position. It has a nice runway of funding from Betaworks and a great problem to solve: surfacing the news that matters. While competitors have given up and joined the flock, has been building the first social news filter dedicated to adding meaning to the unrelenting jabber of online news.

I hate "It's-the-this-of-that" tech news stories, but I hope this comparison is meaningful: What Instagram is to photos and Path is to personal moments, is to news. It's a one-thumbed way to connect with people over the news of the day. You can download it from the App Store for free and see what I mean.