Lexi Reese, Google's newly appointed director of sales for the DoubleClick Ad Exchange in the U.S., plans to focus on meeting with 30 clients in the next 30 days.

The goal is to answer questions from advertisers and publishers participating in what Reese calls a "stock-market-type approach" to buying and selling ad space. Hundreds of thousands of AdWords buyers and more than one million AdSense publishers participate in the exchange, she says.

Google announced the appointment Tuesday, but Reese took the post last month. Her passion for creating an efficient marketplace led her from the most recent Google post of director for the Google Content Network. That's where she worked to help advertisers run display ad campaigns across the network of more than a million publisher Web sites.

Reese describes the ad exchange as a seat on an airplane. Sometimes airlines can't sell the few remaining seats. In the ad industry, these seats turn into ad space remnants. The exchange helps publishers find the advertisers looking to buy the space to run the ads.

"In this ad space, yes -- the planes are taking off fully sold," she says.

Traditionally in display advertising there are hundreds of thousands of sites, along with hundreds of thousands of buyers. So, when advertisers buy ads, it takes hundreds of thousands of hours, but Google's exchange aims to automate that process in an auction-style format, Reese explains. "Suddenly buyers of ads can find sellers easier," she says.

Reese declined to expand on Google's plans for Teracent, which is part of the search engine's broader display strategy. Google reported Monday the intention to acquire Teracent.

Scott Spencer, the Ad Exchange product manager who engineered the platform, says to expect new features in the near future.

As for Reese, the new mother of a baby girl joined Google in March 2007 as the head of Google's online sales team in Boston. She has managed the Mountain View, Calif. company's social media advertising sales team.

Prior to joining Google, Reese served as senior director at American Express and worked in the small business division, OPEN. She holds a Bachelors of Arts degree from the University of Virginia, and an MBA from Harvard Business School.