Could Siri, the voice-based virtual assistant for every iPhone 4S owner, constitute a threat to Google's Android operating system?

Absolutely, says Gary Morgenthaler, a partner at Morgenthaler Ventures, recognized expert in artificial intelligence, and a Siri board member and investor. Apple, he argues, now has at least a two-year advantage over Google in the war for best smartphone platform.

"What Siri has done is changed people's expectations about what's possible," Morgenthaler said in an interview with Mashable. "Apple has crossed a threshold; people now expect that you should be able to expect to speak ordinary English — and be understood. Siri has cracked the code."

This threshold, from mere speech recognition to natural language input and understanding, is one that Google cannot cross by replicating the technology or making an acquisition. "There's no company out there they can go buy," Morgenthaler says.

Google has Voice Actions, a voice search application for Android. So what's the big difference? It comes down to semantics, Morgenthaler says: "Siri understands what you mean." She has a far more precise understanding of what you're saying and the context you're saying it in, in other words.

Morgenthaler calls Google's Voice Actions a "capable speech recognition program," and says it was the state-of-the-art voice-based user interaction program. That was, until Siri, with all her semantic prowess, debuted on iPhone 4S. (Of course, Morgenthaler may well have a financial stake in Siri's future; the terms of the company's sale to Apple were never disclosed.)

Currently, Google is making dismissive public pronouncements about Siri: "your phone shouldn't be your assistant," Android chief Andy Rubin told the AsiaD Conference. But Morgenthaler believes they're scrambling to catch up behind the scenes, because Apple won't stand still with this technology.

Rather, it will use Siri to solidify the strength of its platform and steal advertising dollars away from Google, he argues. "Siri is a platform," Morgenthaler says. "It's not just limited to those things that Apple has done at launch."

At the moment, Siri has a lot of iPhone-centric functions. But Siri the company implemented more than 45 APIs prior to being acquired by Apple — meaning the possibilities of a conversation interface to the web are endless. Back in April 2010, just after the Apple acquisition, Mashable noted Siri's potential role as a driver in mobile search.

"Apple has the opportunity to outmode the entire Android ecosystem," Morgenthaler says. Of course, that hinges on Apple making those APIs available to iOS developers, but he believes Apple will do just that: "This will be the differentiating factor in the iOS platform."

Siri's threat to Google could reach further than Android. In fact, Siri challenges Google's entire search empire and shakes it to the foundation, Morgenthaler says.

"Google has made a huge contribution to all of our lives … they've made search comprehensive and instantaneous … but the whole paradigm is wrong," he says. "[People] don't want a million blue links, they want one correct answer. All the rest is noise that you'd rather have go away.

"Apple has the opportunity to really understand the question that you're asking, and apply semantic knowledge such that [Siri] will deliver you the right answer, or a small set of highly relevant answers."

When that happens, Morgenthaler says, all the steps that typically comprise an online search, including the ads served against search results, become completely irrelevant. He believes Apple can and will circumvent this search experience, passing consumers to merchants by way of Siri — and earning a finders fee for doing so. Under this paradigm, Google could be completely forgotten.

In short, forget the search engine — Siri will be an answer engine. She can perform executable actions and change consumer expectations in the process.

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