Former top Yahoo advertising exec David Karnstedt (pictured here), who has been parked at a Silicon Valley venture firm since he left the company, has been named president and CEO of Efficient Frontier.

Interestingly, another former Yahoo (YHOO) exec, Ellen Siminoff, has also been CEO at the Sunnyvale, Calif.-based search engine marketing firm. She is now chairman.

Karnstedt, who was SVP of of Yahoo’s North American sales until last fall, replaces James Beriker.

He has most recently been an executive-in-residence at Redpoint Ventures, an investor in Efficient Frontier.

Here is an interview I did with Karnstedt in 2007, when he was at Yahoo.

And here is the full press release:

Efficient Frontier Names David Karnstedt as President and CEO

Former Redpoint Ventures Executive-in-Residence and Senior Vice President of Yahoo!’s North American Sales Brings Extensive Experience to the Post

Sunnyvale, Calif. – April 2, 2009 – Efficient Frontier, the worldwide leader in Search Engine Marketing (SEM) technology and services, today announced that David Karnstedt has been named President and Chief Executive Officer of the company.

Karnstedt most recently was an Executive-in-Residence at Redpoint Ventures, an investor in Efficient Frontier. Prior to Redpoint, he served as Senior Vice President of Yahoo!’s North American Sales with responsibility for more than $3 billion in revenue. During his tenure at Yahoo!, he successfully led the integration of the Search and Display sales teams into one central unit and helped establish Yahoo! as a recognized leader in both display and search marketing.

“We feel incredibly fortunate to have someone of David’s caliber join Efficient Frontier at this point in the company’s life cycle,” said Ellen Siminoff, Chairwoman of Efficient Frontier’s Board of Directors. “David’s extensive experience in the Internet space – specifically search – will be a huge asset as he leads the company forward.”

Karnstedt’s experience includes several industry firsts. Prior to Yahoo!, David led the Direct Sales team at Overture Services, the company that pioneered the paid search industry and was acquired by Yahoo! in 2003. He also served as Vice President and General Manager of Alta Vista, where he was responsible for the consumer business and helped shape product development and marketing strategies that leveraged the auctions-based search approach. Prior to Alta Vista, David served as Western Advertising Director at Wired Digital where he helped to develop some of the first advertising models on the Web. He is also active in the industry, having served on both the Advertising Council and Interactive Advertising Association’s Boards of Directors.

“As the leading global Search Engine Marketing company, Efficient Frontier has built tremendous assets –
including its technology platform, a global presence and a great team,” said David Karnstedt. “I plan to build on these key assets by expanding the company’s leadership in search, diversifying into complimentary product offerings and increasing its global presence. I am pleased to lead the company into its next phase of growth.”

Karnstedt is replacing James Beriker, who held executive positions at the company since April 2007 and was its President, CEO and a member of the Board of Directors from February 2008 until March 2009. The company’s business expanded significantly while James was CEO. We are appreciative of his efforts and contributions.

Everyone who wondered why Randy Falco and Ron Grant were still running AOL gets an answer: Time Warner (TWX) was lining up their replacement.

Google (GOOG) sales chief Tim Armstrong becomes chairman and CEO of the troubled Web property, effective immediately.

The move is getting immediate cheers from current and former AOL employees I’ve talked to. The snap consensus is that anyone would have been better than Falco, a longtime NBC executive, and Grant, who was Time Warner CEO Jeff Bewkes’s chief lieutenant before being elevated to his role as President and COO of AOL.

But they’re particularly happy to see a sales guy running the organization: AOL once had a much admired sales operation. But in recent years, the group has been roiled, as a series of sales chiefs came and went. (From Kara Swisher, here are more details on the shakeup, and an interview with Armstrong. And here’s some early betting on Armstrong’s replacement at Google — former Doubleclick CEO David Rosenblatt has a lot of fans).

The current AOL sales chief, former Yahoo (YHOO) sales boss Greg Coleman, was installed just last month. He’s been deep into a reorg of his own.

It was desperately needed after AOL’s miserable performance in 2008, which concluded with a quarter that saw ad revenue drop 18 percent. But those plans may be up in the air now.

In any case, here is the full press release from Time Warner about the firing of Falco and Grant, after the jump:

NEW YORK, March 12, 2009–Tim Armstrong, Google Senior Vice President, has been named Chairman and CEO of AOL, LLC, Time Warner Inc. (NYSE:TWX) Chairman and CEO Jeff Bewkes announced today. Current AOL Chairman and CEO Randy Falco and President and COO Ron Grant plan to leave the company after a transition period.

In making the announcement Mr. Bewkes said: “Tim is the right executive to move AOL into the next phase of its evolution. At Google, Armstrong helped build one of the most successful media teams in the history of the Internet–helping to make Google the most popular online search advertising platform in the world for direct and brand marketers. He’s an advertising pioneer with a stellar reputation and proven track record. We are privileged to have him preside over AOL as its audience and programming businesses continue to grow and its advertising platform expands globally. He’ll also be helpful in helping Time Warner determine the optimal structure for AOL.”

Tim Armstrong said: “I’m very excited about the opportunities presented in leading AOL. AOL has a wide-ranging set of assets and audience. The company is well positioned to enhance those assets into a larger share of the Internet audience and advertiser communities. AOL and Google have been partners for years and I look forward to collaborating with Jeff Bewkes and his team as we explore the right structure and future for AOL.”

Mr. Bewkes added: “Randy led AOL in its transition from a subscription business to an audience business. Under Randy and Ron, AOL’s programming sites exhibited year-over-year growth in unique visitors for 23 consecutive months with many of its sites now in the top five of their categories. They also assembled Platform-A, the number one display ad network in the U.S. with a reach of more than 90%. They also aggressively cut costs as they restructured the Audience business portion of the company into three distinct operating units: People Networks, MediaGlow, and Platform-A. As Randy and Ron move on, they leave AOL with our gratitude and appreciation for remaking the company and bringing it to a new and promising level.”

Tim Armstrong was a member of Google’s Operating Committee and served as the president of the Americas Operations. Under the Americas Operations, Armstrong’s team managed publishers and advertisers’ relationships and platforms with some of the world’s most widely recognized media and agency brands.  Armstrong started at Google in the year 2000 and opened the first office outside of the Mountain View, CA headquarters.

Mr. Armstrong joined Google from Snowball.com, where he was vice president of sales and strategic partnerships. Prior to his role at Snowball.com, he served as director of integrated sales & marketing at Starwave’s and Disney’s ABC/ESPN Internet Ventures, working across the companies’ Internet, TV, radio, and print properties. He started his career by co-founding and running a newspaper based in Boston, MA, before joining IDG to launch their first consumer Internet magazine, I-Way.

Mr. Armstrong sits on the boards of the Interactive Advertising Bureau (IAB), the Advertising Council, and the Advertising Research Foundation, and is a trustee at Connecticut College and Lawrence Academy. He is a member of Mayor Bloomberg’s MediaNYC 2020 committee.  He is a graduate of Connecticut College, with a double major in economics and sociology.