I’ve been covering the VoIP space since 2004, and lately it seems like every other press release sent my way is from a company announcing the addition of an application programming interface (API) to its telephony platform. The promise of APIs is that they make it easy to integrate different services — even those provided by different vendors — into a single application. The press release from one carrier even went so far as to claim that its API would “boost innovation and development of new apps exponentially.”

But is simply providing an API to your telephony infrastructure enough to prompt the world to beat a path to your door? Don’t count on it.

To be sure, these APIs are necessary, particularly in the world of voice mashups. Voice mashups combine voice as well as data and applications across multiple systems to create a new, useful service.

One example of a voice mashup is Twitterfone, a free service that takes your voice, converts it to text and sends it to Twitter. MAXroam provides the overall infrastructure and inbound telephone numbers, Dial2Do does the speech-to-text part, and Zong provides some inbound SIP termination. APIs are needed all around — including on the voice side — to make this happen seamlessly.

Voice mashups can be useful in the business space. They can save a ton of money, and can help to enforce both business process quality and consistency. Imagine calling an airline and speaking to an interactive voice response (IVR) system. A certain percentage of calls could easily be handled by the IVR, which can ask all the correct questions to ensure customers have the right information.

There are, of course, times when speaking with a live human being is necessary. So imagine that all the data collected by the IVR about your call is then sent to a customer service representative so that by the time the two of you are connected, they already know exactly why you’re calling. The call could even be routed to a particular rep based on the reason you’re calling.

This is the power of a voice mashup — the ability to treat voice and data interchangeably. While large companies have been able to afford the cost of developing these custom voice mashups, tools and services are now becoming available that let you make your own.

Jaduka started out by providing a voice API to their telephony infrastructure, which is maintained by their parent company, NetworkIP. But Jaduka quickly discovered that while developers signed up for the API, few were actually using it to launch services. The company now offers customized voice-enabled applications to enterprise customers.

Jaduka’s customers currently use over 4 million minutes a month, a number that is trending upward. But that’s a drop in the bucket compared to the more than half a billion minutes a month their parent company serves.

Ifbyphone provides a number of voice-related small business services as well. They also offer a voice API, but it’s essentially driven by web forms, which makes it easy to integrate their telephony services into any web site without needing to be a programmer.

And while not everyone agrees that what Ifbyphone provides would qualify as a proper API, it does offer a range of useful services to small businesses, such as interactive voice response, intelligent call routing and voice broadcast. They are all designed to help small businesses interact directly with their customers in the most efficient manner possible.

Indeed, APIs enable some great solutions. But APIs aren’t solutions in and of themselves. Nor do they necessarily make money.

Consider Ribbit, a company whose business model is to make telephony available through APIs. The thinking is that they’ll make their money on revenue shares as developers create interesting applications.

If Jaduka’s experience is any indication, however, I don’t expect Ribbit will last too much longer without a complete change of strategy. Ribbit might have 4,000 developers, but how many of them are actually making applications on which Ribbit is able to share revenue? I don’t put a lot of stock in the rumor that BT has purchased Ribbit for $55 million.

Even where you’ve got more than just an API, such as the case with Jaduka and Ifbyphone, the prospects for making a pot of money just don’t seem that great. The combined revenue of Jaduka and parent company NetworkIP is thought to be north of $150 million a year. Assuming Jaduka’s share of minutes per month also translates into share of revenue, that suggests Jaduka is responsible for $1.2 million of the revenue. Ifbyphone would not disclose customer numbers or revenues.

I think the market has a lot of potential, but so far, that’s about it. Go ahead and make those telephony APIs available, but don’t expect the world to beat a path to your door, and don’t expect to make any money just by publishing APIs. Figure out who your customers are, find out what problems they have, and develop solutions to meet their needs. APIs can certainly be a part of the overall strategy, but relying on APIs alone to generate revenue is a pipe dream.

The big buzz of the evening is that Twitter, a San Francisco-based start-up that allows anyone to post short up to 140 character messages to its platform and thus broadcast them to one or many using different media such as web and mobile, is about to acquire Summize, a Potomac Falls, VA-based start-up that uses the Twitter API to search and find relevant messages on Twitter.

The rumors of the deal were first reported by a little known blog (not anymore of course) by Josh Chandler. Subsequent to the news, I made a few phone calls and did confirm that it is not just a rumor and a deal is certainly in the works. It is likely to be announced as soon as next week. I am still trying to dig-up the financial details and would report further when I get hold of them.

The deal would be a good move by Twitter, and would be putting some of its recently acquired $15 million in VC funding to decent use as it would help the company get hold of of a business model. Here is why. Most people think of Summize as a Twitter search utility and it is a might fine search service. It is so good that there are nearly half-a-dozen other start-ups that are using the Summize API. On first blush, it seems like Twitter could bolt on search on their platform and make it more useful. I think it would be thinking about Summize in a limited sort of a way.

“We monitor collective attitudes being expressed right now on the web,” is how Summize describes itself. In other words, it can quickly look at data coming from conversational sources - RSS feeds and Twitter tweets - and offer a quick opinion on what is being talked about. For instance, on this page you can find out what people really think of this deal between Summize & Twitter deal. All the data is coming from the twitter stream.

In a conversation earlier this year, CEO Jay Virdy, formerly of AOL told us that they had developed a way to geocode public timeline tweets (Short messages). This allows one to find out what people are saying about John McCain in Phoenix vs San Francisco?

In other words, Summize has come-up with a clever way of peering through Twitter’s vast data stream and finding out what’s hot, where and how. The results are essentially keywords - topic, person or location based - and thus can be used to show contextual advertising next to the pages that show these results. Summize, has thereby developed an ability to monetize conversations without being intrusive.

Summize could have easily done this on its own, and started to make money. It would surely need to compete for attention with Twitter, and figure out ways to keep generating more traffic. Instead, if Summize is bolted onto Twitter, it can help the tiny start-up get instant traction.

Just as AdSense serendipitously turned Google into a giant cash register, with Summize, Twitter can take first step towards a business model. Of course, Evan Williams & Company have to quickly figure out ways to fix their patchy-at-times service before everyone decides to switch loyalties to one of the many Twitter rivals currently being plotted by clever minds.

PS: Since Twitter doesn’t want to charge me for having too many followers, and it doesn’t cost me anything, go ahead and follow me on http://twitter.com/om. Not that you are going to read the tweets anyway

PS#2: My jet lag has finally hit so if you notice errors/mistakes, please excuse my tardiness. I will rectify when I wake up.