In a blog posting Monday, Google said it's now possible to use an existing phone number as the system 's entry point, although that approach comes with fewer features. The move seems to be part of a carefully constructed game plan.

"I think it's important," said Josh Holbrook, a director in Yankee Group's Anywhere Enterprise research group. "It is one more example of Google simplifying people's lives. They are eliminating and unwinding years of complications and craziness that only a monopoly can create. Google is systematically unwinding this, and that is good news for consumers."

Not All Google Voice Features

The posting said, however, that folks using their own phone number will only have access to a scaled-down version of the service. These customers will get online voice-mail search; automated voice-mail transcriptions; custom voice-mail greetings for different callers; e-mail and SMS notifications; and low-priced international calling.

Those using Google numbers get those features and several others, including a single number that reaches all phones; SMS via e-mail; call screening; listen-in features; call recording; conference calling; and call blocking.

Jeff Orr, senior analyst for mobile content at ABI Research, likes the idea. "The idea of using mobile voice mail is interesting," he said. "I think it has merit because some people find mobile operator-supplied voice mail to be cryptic and lacking in functions. The ability to be able to route calls to Google Voice would be of value."

Part of the Game Plan

Sara Jew-Lim, a Google spokesperson, wrote in response to e-mailed questions that the option always was in the cards. "We know that not everyone wants to switch to a new phone number, so we wanted to provide a choice for people who are willing to trade some features for the ability to use their existing phone numbers."

Holbrook said small companies with as many as about 20 employees -- companies that often use consumer products -- may be interested in Google Voice, but that it's of little interest to enterprises. He expects Google to continue to systemically bridge the gaps between traditionally disparate telecommunications and IT products and services through such tools as Google Voice, Google Wave, the Chrome browser, and the Android mobile operating system.