The line is blurring between the enterprise and the Web. Mashups live on that porous perimeter, offering the reusability of an SOA plus very rapid development using prebuilt services outside the firewall. Soon, we may live in a world where it’s difficult to tell where the enterprise stops and the Web begins. It’s scary — and exciting at the same time.

But just having the ability to create mashups doesn’t mean they’ll be valuable. You need to properly provision and manage the services available for mashups and understand their purpose and place in an SOA. (See also "Mashup platform vendors.")

The task is threefold. First, you must prepare existing infrastructure to support mashups. Second, you need to understand your requirements. And third, you’ve got to wrap your head around the potential value that mashups can and cannot bring.

Although mashups originate with Web 2.0, which epitomizes development on the fly, mashups in the enterprise require preparation. You need to build and support an SOA that’s “mashable” with services and content, as well as with APIs that are both local and remote to the enterprise. Among other things, that means existing enterprise application services must be able to access Internet-hosted services safely.

With the rediscovery of AJAX (Asynchronous JavaScript and XML) technology and the mushrooming popularity of rich Internet applications, we now have the ability to create mashups that quickly solve business problems by using the standard dynamic interfaces that front services. Mashups provide powerful ways to take existing applications and services and create something even more useful for business.

Combining, creating, and cohabiting
Google Maps mashups, which hook the wildly popular mapping service to some database that includes street addresses, have become almost cliché. Yet this type of solution is actually a perfect demonstration of the value of the mashup notion: Somebody has a need, takes a few days to create the mashup solution, and there you have it.

More complex mashups approach composite applications (those that are made up of many services), an advanced SOA concept. For instance, you could mash up a customer database with marketing metrics, then mash up the results even further with sales forecast processes. You own and maintain some of the information and services; some are accessible over the Internet.

So, who’s providing these services? SaaS (software as a service) players such as Salesforce.com seem to have the largest number of enterprise-class services, with service marketplaces such as StrikeIron in the mix, as well as services from vertical sites such as finance, retail, and health care. All have provisioned services, data, and content that are consumable over the Web.

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Even more complex solutions are possible — such as mashups that become sophisticated business processes, applications, or sets of services in themselves. You can see where this is going: full-blown services, processes, and composites that span from your new SOA to hundreds of Web-based services hosted by SaaS players, commercial Internet properties such as Google, and vertical market exchanges.

The big Web players clearly have bought into this vision and are now working on the mother of all SOAs in support of emerging enterprise SOAs and mashups. Google may have been first, but Microsoft, Yahoo, and others are close behind.

Breaking out and mashing up
Although enterprise mashups are new, their solution patterns are already emerging. Broadly speaking, there are really two types of mashups: visual and nonvisual.