Google announced you can now see third-party apps in your Google Now cards on Android. This only works on Android with about 30 or so third-party apps.
So instead of getting your customary Google Now notifications on traffic, weather, flights, tracking packages and so on - you can now get data in your Google Now cards from third-party sources outside of Google.
For example, here is a picture of the Airbnb app as a Google Now Card:
You can see the example cards over here if you want to see them.
Google has partnered with select app developers for this and has not explained how to get your app included here yet. It is unclear when and if Google will expand it to more developers.
The list of partners include Airbnb, Instacart, Pandora, Shazam, Lyft, TripAdvisor, KAYAK, eBay, Walgreens, Ford, Waze, Strava, Duolingo, Mint, The Economist, The Guardian, Belly, Coinbase, Redfin, Zillow, Life360, Hootsuite, Wattpad, Runtastic, Delivery Hero, Hailo, mytaxi, busuu, ESPN, Housing, ICICI, Meru Cabs, Shaadi, The Economic Times, Cookpad, SmartNews, Suumo, BookMyShow and Lincoln.
Forum discussion at Google+.