Google Inc.'s hot new software enables users to make cheap international calls, consolidate multiple phone numbers into one voice mail account and get e-mailed transcripts of their voice messages.
But on Tuesday, Apple Inc. declined to make the call for its iPhone users.
The Cupertino, Calif., electronics giant refused to allow Google to distribute its Google Voice application on iTunes, shutting out iPhone users from easily tapping into the much-anticipated service.
Apple declined to comment on its decision, which sparked outcry from bloggers. Computer magazine PC World accused Apple of having "control freak tendencies." TechCrunch, a well-known blog, called Apple "rotten to the core."
More sanguine analysts, however, said Apple was simply protecting against encroachment from a potential competitor and shielding its business partner, AT&T Inc., from losing revenue from subscribers who would use Google Voice to bypass the carrier's calling and text messaging services.
"There's some turf to protect," said Martin Pyykkonen, an independent technology analyst. "From Apple's standpoint, why embrace something that could end up being a competitor down the road?"
Google has not revealed how it plans to make money from the largely free software, which is based on technology it bought in 2007 when it acquired a start-up called GrandCentral. Mountain View, Calif.-based Google relaunched the service as Google Voice two weeks ago, but only for users who signed up and received an invitation from Google to try out the service and for previous GrandCentral subscribers.
"We work hard to bring Google applications to a number of mobile platforms, including the iPhone," said Carolyn Penner, a Google spokeswoman, who noted that users may still access the application through the phone's Web browser, even if they can't download the application from Apple's online iTunes store. "We will continue to work to bring our services to iPhone users, for example by taking advantage of advances in mobile browsers."
Google Voice, as it functions on a mobile device, differs from Internet phone services such as Skype in that it does not require a Wi-Fi connection. Instead, it hops onto the carriers' cellular network to route calls.
Google Voice, in short, consolidates multiple phone numbers -- home, BlackBerry, cellphone, work -- into one number. Calls to the Google Voice number would ring at all the locations set by the user, who can specify which devices should ring depending on the caller. Calls from the boss, for example, could be set to ring only on a Blackberry and work phone; calls from a mother-in-law could be sent directly to voice mail. Google Voice also generates transcripts of voice mails for users to read and search.
"If you use Google Voice tremendously, it would take away from AT&T's minutes," said Richard Doherty, an analyst with Envisioneering, a technology research firm. "The fear is that Google could dump you into a chat room with all of your friends and you may end up not needing AT&T."
Apple has granted AT&T the exclusive right to provide cellular service for the iPhone in the United States. In return, the carrier subsidizes the cost of the device for subscribers who sign up for long-term service contracts. The relationship has greatly benefited AT&T, said Charles Golvin, an analyst with Forrester Research.
"AT&T subscribers with iPhones spend at least twice as much" on services as customers who don't have iPhones, Golvin said. He estimated that iPhone users spend more than $100 a month on average with AT&T, and that subscribers without iPhones shell out a little more than $50.
"A lot of iPhone users opt for large text messaging plans," Golvin said. "They're also heavy voice users. All of that adds up to higher average revenue across the board."