Now Google offers phone calls over the Web to landlines or cellphones via Gmail.

The service puts Google into direct competition with Skype (124 million users worldwide). Also it makes Google a more ubiquitous part of people's social interactions by uniting the service for phone calls with e-mail, text messages and video chats.

Calls to numbers in the United States and Canada will be free at least through the end of the year. International calls are really cheap.

Gmail has offered voice and video chat for two years, but both parties must be at their computers.