BT (British Telecom) has acquired Silicon Valley-based Ribbit for roughly $105 million, according to various news outlets. Rumors of the deal first emerged on Venturebeat, though company officials vociferously denied any deal. Our sources say the delays were mostly due to internal issues at Ribbit.

Michael Boustridge, President, BT Americas said: “The Ribbit platform makes it simpler, cheaper and faster to build communications functionality into applications, enabling developers to introduce new revenue-generating voice services in hours, rather than weeks. By combining the Ribbit platform with BT’s existing web services, we have the potential to deliver some of the world’s finest applications for communications innovation benefiting consumers and businesses alike.”

As we have pointed out before, there seems to be a lot of interest in merging voice with Internet applications, but the whole process hasn’t been a slamdunk. Dameon Welch-Abernathy, in his post earlier this month pointed out:

… 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?

Taking that into context, this is a great exit for Ribbit founders Tedd Griggs and Crick Waters — and for Mountain View, Calif.-based Ribbit’s backers: Alsop Louie Partners, Allegis Capital, KPG Ventures and Peninsula Ventures. Ribbit was long on hype and underwhelming on end results.

As far as the buyer is concerned, I am not sure how much of a benefit BT is really going to see from the deal. BT has always been long on promise, but short on execution of its grand vision. Its 21CN is a perfect example. It was supposed to be this new network and a platform that would enable new services and seamless bandwidth. Someday it will.

The 21CN plan included a platform that allowed developers to embed voice into internet applications. That platform still exists, but one wonders if anyone is using it. So perhaps it had to go out and buy what is essentially a Class Five switch with a pretty Internet interface.

Ribbit, as an independent company, was able to get some — not a lot — of developer interest. I am not sure how BT is going to do that. It is, after all, a telecom operator that wants to operate like an Internet company. Sure, in a circus you can make a dog walk on two legs as well.

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.

Ribbit, a Mountain View, Calif.-based company that is pushing a VoIP platform that marries web with voice is subject of acquisition rumors this evening. VentureBeat reported that the company was close to being acquired by British Telecom (BT), but later changed their story. When contacted by me, Don Thorson, Ribbit’s Vice President of Marketing dismissed the rumors but declined to comment any further.

It wouldn’t surprise me if BT (or some European telecom) acquired Ribbit (or any other platform) to expand across the borders and find a way to stay relevant. We had pointed out that a consortium of incumbent carriers were developing their competitor to Skype. Ribbit-type platform could be used to develop apps for the incumbent supra-net.

Ribbit has so far raised $13 million from Allegis Capital, KPG Ventures and Alsop Louie Ventures. The company has attracted about 4000 developers to its platform, though it is hard to tell if it is making any revenues from its platform. Over past few weeks, I had heard about Ribbit being in “play” and talking to likely buyers, but there is nothing concrete to add.

Jajah, one of the many callback service providers, is slowly trying to transform itself into a voice platform, offering others the ability to use its network and back-end billing and fulfillment infrastructure. It struck up a partnership with Jangl back in November 2007. This managed services focus seems to have gotten a big boost, thanks to a deal with Yahoo. Yahoo and Jajah share a common investor: Sequoia Capital.

Jajah co-founder Daniel Mattes tells our friend Alec Saunders that Yahoo will outsource voice services for their 97 million Yahoo IM users to Jajah. Mattes says it now has 10 million users, about 8 million of them joining Jajah over the past 12 months. I guess if you include widget users and people using services on other networks, the 8 million additional Jajah users starts to make sense.

If Yahoo is turning to Jajah for voice on IM, then AOL wants to offer others an ability to integrate AIM Call Out service via its Open Voice APIs into softphones, as well as SIP-enabled hardware and cell phones with Wi-Fi connectivity. AIM Call Out is a pay-as-you-go outbound voice calling service built right into AIM.

Jajah, AOL Open Voice, Ribbit and scores of others are taking a platform approach to VoIP, hoping that adding voice to applications will drive up minute volume and turn them into a viable business.