Seattle-based Marchex swung to a profit in the third quarter, as the company continued to grow its phone-call advertising business.

For the quarter ended Sept. 30, Marchex reported a profit of $1.2 million, or 3 cents a share, compared with a loss of $547,400, or 2 cents a share, in the same period a year ago.

Sales in the third quarter reached $39.9 million, up more than 64 percent from $24.2 million a year ago and in line with analyst estimates.

"Since we launched our Pay-For-Call product in July of 2009, every quarter has provided evidence that validates our early decision to focus on the digital call advertising opportunity," Chief Executive Russell Horowitz said in a release. "We made the early bet that the emergence of mobile and other call media sources, combined with deep call analytics, would transform how both large and small advertisers bought and measured phone calls as a lead source."

The company said it expects sales of more than $40 million in the fourth quarter and $148 million to $149 million for the year.