Last week we launched a new column called "Web API Expert," in essence, to provide a deeper focus on the emerging number of Web APIs out there, and show how to leverage them for mashups or other applications. This is the most exciting and interesting area of the emerging Web right now, and the more you understand what's coming, the better you can take advantage.

Keep in mind that the core value of Web APIs are their ability to produce and/or consume information or functional behavior, machine to machine, server to mashups, or server to any Internet-connected application. Thus, you can mix and match information and behavior from any number of sources to form a business solution. Some of these sources you own, some perhaps you don't. These are typically non-visual services, and the interaction is happening behind the scenes. The power of this concept is that you don't own nor host these services; many are free and/or at low cost to you. Thus, the value proposition is speed, agility, and efficiencies.

How do you find the thousand of APIs out there scattered among hundreds of API providers? Just as we needed a mechanism to find Web content back in the '90s and search engines appeared, new directories are appearing, and will continue to appear, allowing you to find the right API. Early leaders include the Programmable Web API directory, with hundreds of APIs already listed, and more added each week.

What's cool about this is that human-readable directories won't be the direction here, but instead shared repositories of APIs/services. In other words, the ability to link to a shared database that contains information about thousands of available APIs/services and have that repository be a part of your existing private service repository. Thus, you have a private repository of services you own exclusively, or that are private, which also include APIs/services that are public.

Considering this within the context of the emerging notion of SOA, you're able to break your existing systems down to a collection of services that can be leveraged within business processes to create business solutions. Along with those services, you can also add thousands of public APIs/services for things such as demographics data, mapping, social networking, messaging, etc., and be able to mix and match these APIs/services, private or public, to create some killer business solutions. This is the emerging concept behind the enterprise mashup.

The trick to getting this concept right is consolidation around public Web API directories or repositories. Indeed, there are some great opportunities for innovative companies looking to consolidate APIs/services within common search and share repository mechanisms that leverage open API interfaces, and with some sort of testing and validation mechanism in place to ensure that the services live up to a specific Service Level Agreement (SLA).

The critical success factor here is the ability to go from a state where the APIs are widely scattered, deployed differently, and are difficult to find, to a shared infrastructure where the APIs/services can actually be discovered and leveraged as if they were local. In many instances I suspect they will be even more reliable than their local, private counterparts when considering that there will typically be more investment in the infrastructure around public APIs/services than services that are intra-enterprise.

While we are waiting for a common directory/repository, or while we're awaiting the existing directory/repositories to refine them, it's still a good exercise to learn how to leverage external APIs/services within your core business applications, even if it's just as a proof of concept. The fact is, our ability to find and leverage the right APIs/services quickly, and leverage those services within your core business processes, could be the secret sauce that allows you to out-innovate your competition.