Yahoo CEO Carol Bartz is making the most substantive changes in her exec ranks since she did a massive restructuring of its staff in late February, according to sources close to the situation.

“She is continuing to clean the place up,” said one top exec about the moves, which are likely to be announced internally tomorrow.

Among the shifts in management will be filling the slot left by the departure of North American Audience head Jeff Dossett in May.

UPDATE: Sources say Yahoo’s head of mobile, David Ko, will get the job of top Audience exec, although it is not clear if he will have the same portfolio has former media heads at Yahoo.

Since Dossett left, his job has been split between Jimmy Pitaro, who runs Vertical Audience Experiences, and Tim Mayer, who is in charge of Search & Social Applications. They both currently report to U.S. EVP Hilary Schneider.

The job of Audience head is a key role, given that Yahoo’s powerful media properties are among its most valuable assets. In recent months, Yahoo has made some major changes in the way it creates its juggernaut News property.

Also to be filled is the job being done by Corporate Partnership SVP Jim Schinella, who, as BoomTown previously reported, is set to leave at the end of the year.

I could not determine who will take Schinella’s job, inside or out.

Interestingly, Yahoo has yet to name an international head.

Sources said the company had filled the position, using a headhunter, but the London-based media exec candidate backed out at the last minute. That meant Yahoo had to restart its search.

There might also be other top exec changes, all part of Bartz’s consolidation of power at Yahoo. She has named a spate of new top execs from outside, but has also kept some from the regime of former CEO and co-founder Jerry Yang.

These staffing moves have come even as a stream of execs continued to depart the Silicon Valley Internet giant, including, most recently, Mike Walrath, who was SVP of advertising strategy. Walrath had led Right Media, the online ad exchange Yahoo bought for $680 million in 2007.

Walrath was widely expected to leave Yahoo in July, at the completion of his earnout from the acquisition, sources said, so the move was more sudden than expected internally.

Sources noted that Bartz moved Walrath’s departure forward in order to announce a new strategy for Right Media focused on premium publishers and to dump those ad networks and publishers of lesser ilk.

Whether this will stop the competitive onslaught in the ad exchange space is an open question given that Google has entered the fray significantly and that Facebook is widely expected to bolster its efforts.

Lastly, several sources said that there are also likely to be more changes on Yahoo’s board, which has seen the departure of two members recently.

In September, Maggie Wilderotter said she would leave the board by year’s end. And former Yahoo nemesis and investor Carl Icahn left the board in late October.

Whether Yahoo will replace them or keep its current size of 10 directors is not clear.

Also possible, several sources said, would be Bartz taking the chairman title, which is currently held by Roy Bostock. Bostock, along with Yang, played a key role in its botched takeover battle with Microsoft (MSFT).

Bartz finally successfully struck a sweeping search and advertising partnership with the software giant this summer, which is moving closer to being launched.

Well, despite the news being as bad at Microsoft as it was at Yahoo (YHOO) earlier this week, the conference call after the software giant released its third-quarter earnings was 100 percent less naughty and 200 percent more glum.

In other words, while there were no F-bombs dropped, there were lots of E-bombs–as in econalypse.

Microsoft’s earnings and revenue took a big hit in its third quarter, with profits down 32 percent from a year ago on a six percent sales decline.

It was the company’s first-ever year-over-year quarterly sales drop.

There were also more than $700 million in charges from layoffs and investment declines, both a result of the weak economy. The culprit for most of the bad news was the decline in consumer and business spending on computers.

And Microsoft CFO Chris Liddell did not even bother to act as if there was any hope, painting a semi-apocalyptic picture of the business landscape that he predicted was not going to get better anytime soon.

Here’s BoomTown’s liveblogging of the call:

2:34 p.m. PDT: The call starts after some very stern marshal music was played. This turns out to be the perfect mood-setter.

First up, the investor relations guy who talks about all the rules, like those folks who come on after, say, a Viagra commercial and quickly list the scary side effects.

But scary was what Liddell was serving up from the get-go, as he pretty much spent the entire conference call talking about just how bad the economy has been, is and will be.

What’s most disconcerting perhaps is the fact that he was delivering the bad news in a cute-as-a-kiwi New Zealand accent.

Nonetheless, Liddell said the company had had to “adapt to a new reality” and that Microsoft was “more cautious than most about the state of the world economy” and–let’s not forget–the “economic pressures are both broad and deep.”

Liddell also noted that the recovery will not happen quickly, but be “slow and gradual.”

Perhaps this is not the right time to mention that both Google (GOOG) and Apple (AAPL) essentially killed in their recent earnings reports.

2:38 p.m.: Microsoft’s investor relations head Bill Koefoed–without any jaunty inflection whatsoever–delivered the numbers in that droning way that all financial types who deliver numbers on calls like this do.

My assistant, Ed, actually fell into a temporary coma from across the room.

Basic message of numbers: Bad.

2:54 p.m.: Back to Liddell for some forward-looking stuff.

Also not good, with consumer sentiment and spending weak, he said, there would be “significant pressure until market conditions improve.”

“In summary, it was a tough quarter,” reiterated Liddell, restating what he already stated and stated again. And then restated.

2:59 p.m.: Now to questions! Maybe things will look up here.

But…nope!

Thus, more worries about Microsoft’s growth, a weakness in sales and even some clucking over renewal rates of its operating system software licenses.

Then someone noted that it seemed as if Microsoft at least had its “arms around” the problems.

Would Liddell show any glimmer of hope?

“I guess we are all learning… how do I feel about the shape of the quarter [to come]?” he pondered.

Wait for it, wait for it, wait for it. Said Liddell, the sad-sack CFO: “I do not see anything that gives me any encouragement.”

Big, big sigh.

3:16 p.m.: Someone asked about one remark Liddell made about some “countercyclical” products, which might be bright spots in the Microsoft empire.

Indeed, new versions of the Windows operating system, Office, Exchange and its search offering are all set to come out in the next year.

Will they be gamechangers? Liddell was not saying, of course.

Finally, at the end, after a question about stock repurchases, there was some light at the end of the tunnel.

No matter what, Microsoft is still a cash-spewing engine.

“One of the great positives,” said Liddell was the company’s free cash flow of $20 billion, at an annual rate.

In other words, there is nothing like money stuffed under the mattress in times like these.

Here is the full memo Microsoft CEO Steve Ballmer sent out to the troops about the big changes in its organization, including the departure of Platforms and Services Division President Kevin Johnson, in which he addresses Apple, Yahoo, Google and more:

From: Steve Ballmer
Sent: Wednesday, July 23, 2008 4:30 PM
To: Microsoft–All Employees
Subject: FY09 Strategic Update

I also have news about an organizational change and a transition in our Senior Leadership Team.

First, I want to thank you for your hard work and the dedication you showed during the past 12 months. FY08 was a milestone year. Our revenue jumped $9.3 billion to more than $60 billion. Operating profit grew 21 percent to $22.5 billion.

These outstanding numbers are the direct result of your commitment to the priorities I outlined last July. A lot has happened since then, but our fundamental strengths, challenges, and strategic goals remain largely the same. Therefore, my priorities are consistent with last year. In FY09 we must continue to:

1. Invest in the right opportunities;

2. Expand our presence with Windows, Office, and developers;

3. Drive end user excitement for our products;

4. Embrace software plus services; and

5. Focus on employee excellence.

By focusing on these five areas, we can continue to grow revenue, increase profit, and expand our market share. These priorities are also critical as we work to address key issues surrounding our business in the coming year:

· Windows: The success of Windows is our number one job. With SP1 and the work we’ve done with PC manufacturers and our software ecosystem, we’ve addressed device and application compatibility issues in Windows Vista. Now it’s time to tell our story. In the weeks ahead, we’ll launch a campaign to address any lingering doubts our customers may have about Windows Vista. And later this year, you’ll see a more comprehensive effort to redefine the meaning and value of Windows for our customers.

We also have to drive developers to create rich applications for Windows. With Internet Explorer and Silverlight, we have great tools for creating applications that run everywhere. But we also need to make sure developers have the .NET skills to write unique Windows applications using Windows Presentation Foundation. To keep today’s Windows applications alive, vibrant, and exciting, we need both—applications that run everywhere and rich client applications.

· Apple: In the competition between PCs and Macs, we outsell Apple 30-to-1. But there is no doubt that Apple is thriving. Why? Because they are good at providing an experience that is narrow but complete, while our commitment to choice often comes with some compromises to the end-to-end experience. Today, we’re changing the way we work with hardware vendors to ensure that we can provide complete experiences with absolutely no compromises. We’ll do the same with phones—providing choice as we work to create great end-to-end experiences.

· Business and enterprise: Our enterprise and server business has never been stronger—today we are on the verge of becoming the number one enterprise software company. We need to continue to push on all fronts—mail with Exchange, business intelligence with PerformancePoint, virtualization with Hyper-V, and databases with SQL Server. We have to drive our enterprise search capabilities, our unified communications solutions, and our collaboration technologies. And we must continue to compete against Linux in key workloads such as Web servers and high performance computing.

· Software plus services: Some people think software plus services is all about search. But it’s really about changing the way software is written and deployed. The future is about having a platform in the cloud and delivering applications across PCs, phones, TVs, and other devices, at work and in the home. It’s also about driving change in business models through advertising, subscriptions, and online transactions. Software plus services is a huge opportunity for us to deliver new value on the desktop and the server to all of our customers. This year at PDC, you’ll hear more about our cloud platform initiatives and the next versions of our Live and Online technologies.

· Google: We continue to compete with Google on two fronts—in the enterprise, where we lead; and in search, where we trail. In search, our technology has come a long way in a very short time and it’s an area where we’ll continue to invest to be a market leader. Why? Because search is the key to unlocking the enormous market opportunities in advertising, and it is an area that is ripe for innovation. In the coming years, we’ll make progress against Google in search first by upping the ante in R&D through organic innovation and strategic acquisitions. Second, we will out-innovate Google in key areas—we’re already seeing this in our maps and news search. Third, we are going to reinvent the search category through user experience and business model innovation. We’ll introduce new approaches that move beyond a white page with 10 blue links to provide customers with a customized view of their world. This is a long-term battle for our company—and it’s one we’ll continue to fight with persistence and tenacity.

· Yahoo: Related to Google and our search strategy are the discussions we had with Yahoo. I want to emphasize the point I’ve been making all along—Yahoo was a tactic, not a strategy. We want to accelerate our share of search queries and create a bigger pool of advertisers, and Yahoo would have helped us get there faster. But we will get there with or without Yahoo. We have the right people, we’ve made incredible progress in our technology, and we’ll continue to make smart investments that will enable us to build an industry-leading business.

As I mentioned earlier, I have important organizational news. Today we are announcing that the Platforms and Services Division will be split into two businesses: Windows/Windows Live and Online Services. We are also announcing that Kevin Johnson will leave the company. He will work to ensure a smooth transition.

Since 1992, Kevin has been a key contributor to many of this company’s most important achievements. As president of the Platforms and Services Division, Kevin has built an incredibly talented organization and laid the foundation for the future success of Windows and our Online Services Business. Over the last 16 years, through everything from his work as head of the company’s worldwide sales, marketing, and services efforts, to his leadership in transforming our field operations and repositioning the company to focus on opportunities in emerging markets, Kevin has played a vital role in this company’s success. There is no doubt that his passion and dedication will be missed.

Effective immediately, Steven Sinofsky, Jon DeVaan, and Bill Veghte will report directly to me to lead Windows/Windows Live. In the Online Services Business, we will create a new senior leadership position and conduct a search that will span internal and external candidates. In the meantime, Satya Nadella will continue to lead Microsoft’s search, ad platform, and MSN engineering efforts, and Brian McAndrews will continue to lead the Advertiser and Publisher Solutions Group. Both Windows/Windows Live and the Online Services Business are led by a strong group of executives on the technical and business side who have the talent and experience to address the challenges we face and drive the next generation of growth and success.

Looking ahead, I see an incredibly bright future for our company. As I said at the June 27th Town Hall for Bill, we are the best in the world at doing software and nobody should be confused about this. It doesn’t mean that we can’t improve, but nobody is better than we are. Nobody works harder than we do. Nobody is more tenacious than we are. We’re investing more broadly and more seriously than anybody else. Our opportunities to change the world have never been greater.

I look forward to working with all of you as we focus on our five priorities in FY09.

Steve