-By Benjamin Palmer

If you’re an active online user over the last few years, you’ve probably noticed that a lot of Web sites and services are becoming more and more compatible with one another. You can plug Twitter into Facebook, Flickr works with Tumblr and Twitter can update your LinkedIn status. In some cases this is happening because developers are using non-proprietary standards so that things automatically play nice with each other, but more often than not it’s because developers have built an open Application Programming Interface, or API.  This means that some functionality of the Web service can be used by third-party developers.

The API you’re most likely to have used (though you probably didn’t even realize it) is Twitter. Anyway you’ve ever used Twitter that was not through Twitter.com used its open API.

If you use a Twitter client on your iPhone, that’s not a Twitter product; it was created by someone else and just plugs in to Twitter’s service using its API. There are third-party apps for Netflix, Facebook and dozens of other popular Web applications because of their open APIs.

In some ways Twitter is actually only in the API business; most of its traffic doesn’t come from anything it owns—it’s all from other apps (desktop or mobile) or through integration with other Web applications. It basically just passes the messages around, but all the sorting and input and reading experiences are created by other companies. The openness of the API has spawned a whole ecosystem of interrelated features, products and integration that has helped make Twitter so popular and part of the fabric of the Internet.

APIs offer some interesting opportunities for brands and marketers, from using existing APIs to make new brand experiences to the creation of something that has its own open API. There are tons of available services online that exist to do one thing really deeply, and your brand’s role in Internet experiences could be curating or modifying some of these services.

If you made a new Twitter application for your brand, what would it do? If your brand is about music, what kind of campaign could you create around the last.fm API?  Foursquare lets you check in at real-life venues and see where your friends are; if your brand is about getting out there, what can you do with Foursquare’s API? Instead of starting from scratch with the features of your online marketing, you can start with proven, existing services and behavior, and get creative from there. 

Another opportunity: a brand could create its own API. A Web service might open its API because it increases the usefulness and longevity of its products, and it can work as free R&D, with the community inventing new products and services on top of your foundation.

Who wouldn’t want that for their brand?

Let’s say your brand was about waking people up. You could create a Web application that’s a wake-up call widget. Instead of just making a minisite and some ads and hoping people pay attention to your wake-up-call thing, if you make an open API for that functionality, developers could make all sorts of wake-up applications based around your feature set.

Suddenly, your brand “owns” the digital wake-up call on the Internet. Anytime anyone wants to have a wake-up call feature in their app, they just use yours and give you some credit. Instead of just trying to connect to other people in one direction, you make something where people are actively trying to connect to you.

Open APIs are part of how the Internet is evolving because it’s the best way for Web services to survive. It creates interdependencies. And the Internet works best when features and ideas are connected and work together. It’s a collaborative medium—it was designed that way from the start. So your brand should be trying its hardest to play well with other Internet features and, when possible, make something new that the rest of the Internet wants to play with as well.

Benjamin Palmer is co-founder and CEO of The Barbarian Group.