MyBantu is an interesting little mashup, available as an iPhone app, an Android app, and a website. Its goal is to make shopping for anything, especially restaurants and movies, easier and more social. It uses Yelp API, Netflix API and various others to make it happen. It's very similar in idea to Siri, the "ultimate mashup" that Apple later gobbled up in the largest mashup acquisition ever.
Payment is a critical piece of any application and new usage patterns have indicated that users are likely to do their purchase from a variety of devices and applications. It is important to create the right experience within the application so that the payment process is seamless to the user. Visa, one of the key players in the payment industry, has announced the launch of its developer program to consolidate all its offerings and push its new digital wallet service, V.me, that is slated to launch in early 2012. The V.me by Visa API is available to developers now for beta testing.
Kyber created an on-chain liquidity protocol so that any app can exchange value through decentralized tokens using cryptocurrencies of choice. Now, Kyber is providing API access to this protocol so that developers without smart contract experience can leverage the on-chain liquidity protocol.