The Enterprise Service Bus (ESB) is the best way to do multi-channel Integration allowing your existing software/application investment to be available to Mobile, smartphone/tablet users faster. It also has the benefits of Service Oriented Architecture (SOA) of being scalable, maintainable, loosely coupled, highly available etc.,
A recent definition from Gartner Terms SOA as a software architecture style that uses server-side, consumer-independent business components, accessed in an interactive manner via documented remote accessible programmatic interfaces. It's modular and distributable.
Service orientated Computing has now come back with a renewed vigor thanks to Mobile/Smartphone era. The mobile era which has contributed to the decline of the PC age has compelled the enterprises to re-think their application architectures. Applications now being built has an additional requirement to be mobile friendly. Some of the customer centric verticles like Banks/Insurance have now realized that survival is impossible unless they allow mobile banking facility.
Platform independence which was more associated with Java/internet makes more sense with SOA, webServices etc., XML allows communication between the service consumer and service provider possible no matter what client is being used.
SOA shifts developer focus from software functions to business functions and therefore aiding rapid business change.