A lot has happened since Ribbit emerged almost two years ago with the self-stated goal (or threat) of being “Silicon Valley’s Telephone Company”: Voice platform plays have come, gone and come back into vogue; the start-up was gobbled up by BT; and the wireless world has exploded with the emergence of mobile apps.

Which is a long way of saying that Ribbit was probably slightly ahead of its time.

The company is trying to make up for that with the launch today of Ribbit Mobile, which leverages the company’s core software platform, network infrastructure and application programming interfaces (APIs) to deliver an advanced call management service that combines all of a user’s phones, a Web interface and mobile applications (running initially on the iPhone and BlackBerry, pending app store approvals).

In the past, Ribbit has tried to interest other telcos in running its services platform, and with the BT acquisition it has become the voice, and platform, of change within one of the world’s largest incumbent telcos. On the product front, its telecom-meets-customer-relationship-management applications are now available for Salesforce.com and Oracle.

But for all that activity, it hasn’t yet had the mainstream breakthrough to match its ambitions. Ribbit Voice, available for a free trial and ultimately as a for-fee service ($30 per month for the full offering) represents its clearest voice 2.0 play yet.

“What used to be a sacred cow, voice, is becoming just another app on the mobile phone,” said Ted Griggs, CEO of Ribbit, who was also recently named chief technology officer of BT Voice. “What voice service you use and what you do with it have become up for grabs. With Ribbit Mobile, this is how we think it should be done.”

The cloud-based Ribbit Mobile service includes familiar features such as follow-me call routing and voicemail transcription that other services, most notably Google Voice, offer as well. But Ribbit offers perhaps the most wide-ranging of all voice 2.0 services, providing features — such as multiple ring, Web-based calling and the ability to make it appear a call is coming from any of a user’s numbers — that Google Voice does not. It also lets customers use all of its capabilities whether they get a new phone number and integrate with existing numbers, something Google is inching toward but hasn’t quite fully reached. Customers can use Ribbit with their existing phones without any Web or mobile apps or leverage client software to expand their experience.

“It takes your mobile device, which really is your identity, and builds the service around that,” Grigg said, describing the feel of the somewhat complex service as akin to “personal CRM.”

In an interview, Griggs stressed the platform aspects of Ribbit Mobile. The service is built on the Ribbit platform APIs, which means developers can take it and extend the service however they like. For instance, the company is counting on third-party developers to build an Android client for the offering, he said. Ribbit announced a developer rewards program to compensate developers for their app development.

The service also runs on what Griggs calls a telco-class telecom back end, including integration with networks from BT and Level 3 to carry calls. It can also terminate calls on voice-over-IP networks like Skype, Google Talk and MSN.

“We don’t talk a lot about it, but our network is really telco-grade,” for instance, able to offer 911 service in the U.K. to meet regulatory requirements there, Griggs said. “The back end of what Ribbit does is very ‘telecomy’ and ‘Internety’ — we bring the two together.”

This isn’t the first mobile service Ribbit has built. It launched a proof-of-concept mobile service, dubbed Amphibian, shortly after the company emerged.

According to a company spokesperson, Ribbit Mobile is the newest version of what was formally known as Amphibian. Ribbit has spent the time since the original announcement beefing up the product and making it ready for mass consumption and building out the features, she said.