AOL CEO Tim Armstrong is the gift that keeps on giving–at least to Greg Coleman.

He’s the Chief Revenue Officer at the Huffington Post, for which the Internet giant just forked over $315 million to acquire.

Sources said Coleman, who has run advertising sales at the privately held news and opinion site since the fall of 2009, will get a multimillion dollar payday from the deal, even though he is not staying on after it closes, since AOL has its own top ad guy.

Except that this is the very same Greg Coleman who had been running ad sales for AOL for only two weeks when Armstrong took over from ousted CEO Randy Falco in February of 2009.

Coleman was gone from AOL by the end of April, replaced by Armstrong with current ad sales head Jeff Levick.

And for those three months of work Coleman got paid out his entire three-year AOL contract.

Not bad work if you can get it.

Actually, many credit Coleman’s energetic work at the Huffington Post for turbocharging its ad sales revenue to $31 million in 2010 and projected revenue upward of $60 million in 2011.

Coleman is an experienced online ad exec who was at Yahoo for seven years, responsible for all advertising revenue worldwide. He came to Yahoo from Reader’s Digest.

But Coleman ran into Yahoo’s management buzz saw after trouble hit the company in 2007. He was one of the first in a long line of execs to leave the troubled company, departing in one of its many controversial reorganizations.

But Yahoo’s ad business did grow strongly under him and former Yahoo ad exec Wenda Millard.

Before AOL, Coleman ran a Los Angeles-based start-up called NetSeer, which focused on ad targeting.

Memo to soon-to-be unemployed Greg: You’re definitely buying lunch next time I see you, and keep in mind that BoomTown is feeling partial to caviar.

As BoomTown reported earlier today, I just got sent the entire internal email–penned and just sent out by AOL CEO Randy Falco–about the replacement of its Platform-A President, Lynda Clarizio, with former Yahoo top ad sales exec Greg Coleman.

AOL also just put out a press release confirming the move.

As new head of the Time Warner (TWX) online service’s ad unit, Coleman has his work cut out for him, turning around a business that has been hit by a severe fall-off of revenue.

“No doubt Greg is joining Platform-A at a difficult time,” writes Falco below. “The deepening economic recession is affecting every corner of the economy, including our own.”

Translation: Yahoo (YHOO) was kindergarten! Get to work pronto, Greg!

Here’s the full memo:

Dear AOL colleague,

Today we are announcing a change in the leadership of Platform-A that will help us build on the unmatched reach of our advertising business and fully leverage the success of our MediaGlow and People Networks businesses.

Greg Coleman, a seasoned advertising sales and publishing executive and former EVP of global sales at Yahoo, has agreed to join us as President of Platform-A, replacing Lynda Clarizio.

Under Lynda’s leadership, we made great progress at Platform-A–consolidating and integrating seven companies; creating a unified organization around sales, technology, operations & product management, technology sales, publisher services, R&D, international, marketing, strategic planning and network development; and expanding overseas. As a result of Lynda’s success in integrating the business, Platform-A today has the largest reach and most advanced suite of digital advertising technologies available anywhere. We all owe Lynda a debt of gratitude for her outstanding contributions to Platform-A.

Now, we have the opportunity to build on this foundation and expand premium branded display sales across our extensive and fast-growing MediaGlow programming network. And Greg, who has 25 years of media sales and publishing experience, is ideally suited to lead this effort.

During his nearly seven years at Yahoo, Greg led the company’s search and display ad sales teams. During that time, Yahoo’s ad revenues climbed tenfold–reaching more than $6 billion–with substantial ad growth in the U.S. as well as Europe, Asia and key emerging markets. For the past year, Greg has been CEO of NetSeer, a start-up focused on next generation search and ad targeting.

Greg understands that online brand building is the next frontier in digital advertising, and whoever can deliver marketers measurably improved branding online will be poised to lead over the long term. His great agency and C-level relationships will help us create breakthrough branding packages that leverage the strong success of MediaGlow and the upcoming developments at Bebo.

No doubt Greg is joining Platform-A at a difficult time. The deepening economic recession is affecting every corner of the economy, including our own. Yet, even in this volatile environment, online advertising remains the most productive, efficient and measurable way for advertisers to reach audiences that are dispersing across an increasingly fragmented media landscape. I’m confident that Greg has the background and expertise to deliver on the promise of Platform-A.

Please join me in welcoming Greg to the AOL family, and in thanking Lynda for her many contributions to Platform-A and wishing her all the best on her future endeavors.

Randy

The game of executive musical chairs among Web companies keeps on going, with sources telling BoomTown that AOL ad head Lynda Clarizio will be departing the online service and replaced by former high-ranking Yahoo ad exec Greg Coleman (pictured here).

Last week, this column first reported on former Yahoo media head Scott Moore taking a similar content job at Microsoft (MSFT), which had been vacated by Jeff Dossett, who took Moore’s job at Yahoo.

The less confusing move at AOL, with Coleman taking over for Clarizio and which has been in the works for only a week, could be announced as early as today, although I have been hearing rumors of such a development since late last week.

Clarizio has been head of Platform-A, the overall name for AOL’s advertising business, which includes a lot of various online ad companies AOL has bought in recent years.

She had been running AOL’s Advertising.com in Baltimore before being tapped to integrate them better over the last year, after a series of ad execs shuffled in and out of AOL.

But, said several sources, as a former AOL lawyer and dealmaker, Clarizio (pictured here) is not regarded by top execs the kind of nitty-gritty sales exec that AOL needs now, as it seeks to revive its fortunes.

AOL’s ad business has lagged badly of late, with owner Time Warner (TWX) pre-announcing that the online service’s results would be particularly weak this quarter. Time Warner reports quarterly earnings tomorrow.

Since a much-chewed-over possible merger with Yahoo (YHOO) has been put on ice, with the recent arrival of new CEO Carol Bartz, Time Warner and AOL execs have decided to focus on strengthening the online service and making much needed changes.

AOL recently announced a 10 percent layoff of its staff of 7,000, part of the rightsizing that has been going on.

And its valuation was also recently written down by Google (GOOG), to $5.5 billion from $20 billion several years ago.

AOL had already been in the midst of renovating its communications and social-networking assets under a new division called People Networks, which is run by former Bebo head Joanna Shields.

Its content arm has also gotten a different blog-centered direction and name–MediaGlow–under Bill Wilson.

Now, it’s apparently time for the ad leg of AOL’s three-pronged new strategy its future business is resting on to be fixed.

The hiring of Coleman came suddenly, said several sources. He had been considering a top job at another well-known online company and also was planning to move to a start-up he has been running to the Silicon Valley area.

He was hired by AOL CEO Randy Falco, whom Coleman has known for a long time, only last week, after Falco heard that Coleman was considering other positions.

Sources at Yahoo said the hiring had to be cleared by the company and Bartz, at Time Warner CEO Jeff Bewkes’s request, due to competitive issues.

Coleman is indeed an experienced online ad exec, who was at Yahoo for seven years, responsible for all advertising revenues worldwide. He came to Yahoo from Reader’s Digest.

But Coleman ran into Yahoo’s management buzzsaw after trouble hit the company in 2007. He was one of the first in a long line of execs to leave the troubled company, departing in one of its many controversial reorganizations.

But Yahoo’s ad business did grow strongly under him and former Yahoo ad exec Wenda Millard. She was also pushed out of Yahoo and now is Co-CEO of Martha Stewart Living Omnimedia.

Since then, Coleman has been running a Los Angeles-based start-up called NetSeer, which focuses on ad targeting.

Given his media background, Coleman is likely to be key to expanding premium branded advertising display sales across AOL’s advertising and programming networks.

He will move to New York and report to AOL President and COO Ron Grant, said sources, although Platform-A has key offices in Baltimore and San Francisco too.