The new program, Google Talk, will compete against similar free services offered for several years by America Online Inc., Microsoft Corp. and Yahoo Inc. All are vying to increase their presence on PCs to boost online ad revenue and name recognition.
"Right now, AOL is the 800-pound gorilla when it comes to instant messaging. Its AOL Instant Messaging Service is used by millions of people," says CBS News Tech Guru Larry Magid. "When it comes to instant messaging, the size of the market does matter because it only works if your friends or business associates are using the same service you're using. So, Google has an uphill battle to win over users."
AOL's messaging program has about 41.6 million U.S. users, followed by Yahoo Messenger with 19.1 million and MSN Messenger with 14.1 million, according to ComScore Media Metrix's July report.
As for the PC-to-PC chat service, Magid notes "the voice service is very nice but it's not unique. There are already a number of free PC-to-PC voice services."
Click here to listen to CBS News Tech Guru Larry Magid put the new Google Talk service to the test, in this podcast interview.
Wednesday's launch of the instant messaging and voice chat services comes two days after Google unveiled its new , which can scour users PCs for files. It also comes less than a week after the company announced plans to raise $4 billion in a secondary stock offering - which some analysts speculated could be used to fund far-flung projects such as Internet telephony.
Users of the most popular instant messaging services are unlikely to switch unless the friends and colleagues on their "buddy lists" do the same. The different instant messaging services still do not communicate with each other, though promises of such "interoperability" have been made for years.
Google is inviting programmers to build its technology into their software.
"It means other people and developers will be able to add value to our network by being able to add this to computer games, productivity applications and anywhere else they want," said Georges Harik, director of product management at Google.
The new Google program features a basic user interface with few graphics, much like the main Google search site. It does not spawn pop-up windows or display ads like America Online's Instant Messenger.
"We'll have an uncluttered interface that allows you to search over your contacts pretty easily," Harik said. "It just stays out of your way unless you want to connect to someone."
Google Talk, which is being released in a beta test version, works only on PCs running Windows 2000 and Windows XP. Eventually, the company plans to release a version for Apple's Mac OS X.
Google Talk also requires users to have an account with the company's free Gmail e-mail system. Gmail previously was available only to those invited by a current account holder, but now Google is opening up registration to anyone in the United States.
Voice chat requires that both the caller and recipient have speakers and a microphone hooked up to their computers. It does not currently offer an adapter to which regular phones can be connected.
And unlike Internet phone services such asand Skype, Google's voice service does not support calls to the regular telephone system.
Harik also made it clear that Google has no intention of trying to become a popular bridge to the other major instant-messaging providers. "We're not going to do anything like force other networks to interoperate with us," he said. "We're not going to arbitrarily break into their protocols."
However, because Google Talk runs on open standards, outside developers who incorporate the service into their programs could try to enable such interoperability.