Who will be the new face of Yahoo in the advertising world? That's one of the most common questions in ad industry circles these days.

Over the last couple of months, Yahoo has been looking to hire a new exec-VP for its Americas business, with the help of exec search firm Spencer Stuart. This is the job that Ross Levinsohn once held and is especially crucial considering that Yahoo's relationship with ad agencies has seen better days.

But it does come with its challenges. For one, it reports to new Chief Operating Officer Henrique De Castro, a strong personality who has a reputation of being difficult to work with. It also could be challenging since Yahoo under Marissa Mayer has positioned itself first and foremost as a technology company -- not a media company.

Still, it's one of the biggest jobs in all of digital advertising, and is one that is expected to pay handsomely.

Here's a list of potential candidates -- some who are said to be in the mix and others who Yahoo would be wise to look at.

Rich Riley
Mr. Riley worked at Yahoo for more than 12 years and briefly held this role during Scott Thompson's short-lived CEO tenure, but departed when he was removed from the position by Ross Levinsohn. Before that, he ran revenue for Yahoo's business in Europe and the Middle East, where the company is a smaller player than it is here in the U.S. Marissa Mayer is said to be a fan of his and his name has been mentioned in recent days in connection with the job. Mr. Riley was said to be in the running for a C-level role at ad retargeter Criteo, but that opportunity seems to have fallen through.

Kathy Kayse
Currently the sales chief at The Oprah Winfrey Network, Ms. Kayse has held senior roles in TV, digital and print. Before OWN, she was a sales leader at AOL and is also the one-time publisher of People. As a result, she's extremely well-rounded and a polished executive who could instantly command respect both inside and outside the company.

David Kohl
Mr. Kohl ran ad sales for online music-video company Vevo up until his sudden departure from the company this week. He previously spent more than a decade in sales roles at Viacom across two different stints there. He is said to be in the mix.

Penry Price
Mr. Price's name is one of the most common ones being bandied about in relation to this job. He, like Ms. Mayer and Mr. De Castro, is a former Googler. Unlike Ms. Mayer and Mr. De Castro, he is well-known and widely respected among agencies and big national brands. He's currently the president of ad-targeting startup Media6Degrees.

Eileen Naughton
Another Time Warner veteran, Ms. Naughton has been at Google since 2007 when she was brought in to bring cohesive messaging around Google's different ad products to brand advertisers. She ran east coast sales there and is now VP of global sales. She's a very experienced executive who does well in front of clients.

JP Colaco
As Hulu's sales chief, Mr. Colaco has been a big factor in the video services' success. He spearheaded innovation around video ad targeting and formats, and is well-known and liked among TV advertisers and agencies. But the company's future is now murky following the departure of CEO Jason Kilar. Before Hulu, he spent more than a dozen years at Disney and also worked at McKinsey, of which Mr. De Castro is also an alum. On the flip side, this is a much bigger organization than Hulu so it might be a stretch.

Laura Lang
While Ms. Lang seems to be a longshot, there are people inside Yahoo who would love to see her in the mix. The Time Inc. CEO will be looking for new work soon, since she will not stay with the company once it's spun out from Time Warner. She would come with deep agency and marketer relationships, having run Digitas, the largest digital agency in the U.S., as CEO before taking the Time Inc. gig. Still, it's unclear if she's willing to take anything less than a CEO role at her next stop.

Here's the job description:

Yahoo EVP Americas