With that disclaimer behind us, one of the distinguishing characteristics of cloud software is the variety of ways it can be integrated. As most cloud applications present themselves as a series of Web services, they lend themselves to a service-oriented architecture, even if they don't follow all the SOA protocols. With the right toolkits and development attitude, you can integrate cloud applications with a variety of techniques...and use as many of them concurrently as you like, even in the same application. Of course, you have to understand the limitations of each approach--but there's nothing wrong with getting things done quickly. Let's look at this as layers of an onion.

Otherwise known as mashups, this style of integration is the ultimate in quick and dirty. The coding exercise is the construction of iFrames for the screen layout and URLs with lots of parameters for grabbing the goodies from the other cloud. This is the baseline method for pulling images, maps, news items, and data feeds from publicly available services like Google or Yahoo. This method will become increasingly powerful (particularly for demos) as graphing packages and other document services become commonplace as cloud services. AJAX can give the pages a modern, intuitive, and responsive UI. Unfortunately, mashups don't inherently offer much in the way of security, so you'll have to look at tricky coding practices and server-side validation (for example, ) for sensitive data, and you'll probably want single sign-on or other authorization infrastructure to control access without irritating users. So the tradeoff at this layer is: simple code and read-only, or secured with complex code.