Jaxtr Inc. has raised $10 million to expand its Web-based service that allow users to make less expensive long-distance calls. It's the second round of funding for the Menlo Park-based company, and was led by Lehman Brothers Venture Partners. The round brings the company's total raised to $20 million.

The service has registered more than 10 million users in 220 countries, said Chief Executive Officer Konstantin Guericke, who said jjaxtr has spent no money on advertising. Guericke was the co-founder and CEO of Mountain View-based social networking site LinkedIn, which raised $53 million and was valued at $1 billion on June 17.

Guericke said he thinks jaxtr has gained traction because it lets users talk through phones instead of through their computers, like many of its competitors in the voice-over-IP market. VoIP allows consumers to use broadband connections to talk more cheaply than with traditional phone service or calling cards.

The company's service generates local numbers for users to call with their phones, eliminating long-distance and international charges, Guericke said. Users must be registered with jaxtr to receive calls, but consumers don't have to register with jaxtr to call the service's customers for free.

Jaxtr has several revenue streams: fees for phone minutes, advertising on its Web site, and advertising on free text messages. Users get free minutes for referrals and for activity on the site but pay 1 cent to 6 cents a minute for additional calls.