As Apple's new iPhone, the 4S, reaches buyers' hands, reviewers are raving about Apple's intelligent assistant, Siri. The virtual helper, which can recognize casual spoken questions and return answers from services like Wikipedia, Wolfram Alpha, and Yelp, is being labeled a paradigm shift in how we interact with computers.

But to truly deliver on that potential, Apple will have to make Siri more powerful than the beta version on the new iPhone, say mobile software developers and artificial intelligence experts. Today, Siri can answer a range of queries from weather forecasts to restaurant recommendations and help with tasks like calendar scheduling, but it's far from a universal helper. For example, Siri can't provide flight times or book movie tickets—which it could before Apple bought the technology last year from the eponymous startup.

"It's clear that it would be technically possible to integrate any Web service into Siri; you can put a Siri front end in front of anything," says Norman Winarsky, who helped transform DARPA-funded research at independent research lab SRI International into the Siri that was bought up by Apple. Winarsky says that combining Siri with other apps would make both the personal assistant and services it plugged into more useful. "People would be happy to optimize their services and apps for Siri," he says. "All those very different user interfaces that have to be built—and we have to learn—can now rely on a very natural, polished user interface built by Apple using Siri." For example, instead of manually tapping through several screens to watch a movie, a person could just say, "I'd like to watch Stanley Kubrick's film AI, please."

Apple's success with the iPhone was in no small part due to its allowing outside developers to create novel apps that brought new technologies and ideas to the device. Winarsky says the same approach could give Siri a boost.