Here’s an interesting irony–Yahoo CEO Carol Bartz will have her 99th day in office on the very one that the Internet giant will announce its first-quarter earnings: April 21, 2009 at 2 p.m. PST.

Technically, it will mean that she has been running Yahoo (YHOO) for 100 days, a time when most administrations get their first evaluation.

Thus, if it’s good enough for President Obama, it’s good enough for Bartz!

While most expect the results for the quarter to be weak, due to the econalypse, the overall verdict from BoomTown’s needling of Yahoos to give me info on their new leader recently: Love, love, love Bartz’s innate decisiveness, and wanting more of the same.

“She has an opinion and she is not afraid to use it,” joked one high-ranking Yahoo. “That is a big deal for a lot of people here who have wanted a CEO who is very forceful.”

And the only substantive negative: Some remain worried about her lack of Internet savvy, although most of those admit she has been a quick learner as the 100-day mark comes to a close.

In Yahoo’s case, 100 days has a special meaning–when he got his job in late 2007, former Yahoo CEO and co-founder Jerry Yang declared that he was going to give the troubled company a 100-day evaluation with “no sacred cows.”

The Yang-farmed bovines, as it turned out, just got fatter.

Under Bartz, more have been under the knife, as the hard-charging exec has started to really put her imprint on the company.

She has certainly talked tough since the meet-the-press conference on her very first day on Jan. 13.

Some memorable Bartz quotes were about Yahoo’s immediate needs, in her estimation: “some friggin’ breathing room” and “frankly, [the company] could use a little management.”

That kind of tough-lady, Annie-Get-Your-Gun quote-making has been Bartz’s signature, whether it be in folksy Friday memos she has sent out to staff or at the fourth-quarter earnings call in late January, only weeks into her tenure, when she declared:

“This is not a company that needs to be pulled apart and left for the chickens.”

Well, except for the management structure, which Bartz pulled right apart and reshuffled six weeks in.

Cleaning up and simplifying the complex reporting structure in an all-roads-lead-to-Carol set-up and tossing out the CFO were main points of the reorganization. Many at Yahoo expect there to be even more cuts in staff sooner than later, many sources said.

And there have also been departures of key staff, including: PR head Jill Nash, Zimbra founder Satish Dharmaraj and soon, high-ranking techie Venkat Panchapakesan.

Yang too, although he remains on the board, has not been present as much at the company.

Curiously, though, except for the new CMO, Elisa Steele–whose office is powerfully located right next to Bartz, as many Yahoos noted to me–there have been no further appointments for open positions for CFO, a new Customer Advocacy top exec and a new international head. Presumably, they are on the way.

Not that Bartz has not been busy–visiting Yahoo staff and clients all over–as well as finally finding time for a face-to-face meeting with Microsoft CEO Steve Ballmer in Silicon Valley recently.

Before the recent meetings, in a classic negotiating tactic, Bartz (pictured here) has projected a disinterested, poker-faced attitude about the situation, even telling Yahoo staff in one meeting “that she plans to spend a lot of time investigating whether to sell Yahoo’s search business, but that her ‘gut’ was not to do that.”

Well, a sale of Yahoo’s search business might not happen, Bartz was only buying a little time in being so confident and projecting the affect that Yahoo had some leverage and a choice.

But that is exactly what she does not really have, given that Yahoo faces the prospect of spiraling costs to maintain a search share, even as it has a good chance of declining.

So, last week, the news–first reported here Friday–that Bartz was involved in preliminary talks with Microsoft (MSFT) about an extensive commercial advertising and search partnership–should have come as almost no surprise.

A re-engagement between the companies, after a bruising takeover battle that ended in tears all around, has been long hoped for by investors and other observers, given that both have struggled against the search behemoth that is Google (GOOG).

(Or, in a nickname that BoomTown is trying unsuccessfully to popularize: Googzilla.)

The talks–which are not about the software giant making another acquisition offer for Yahoo–are ongoing and might not lead anywhere, but it is in both sides’ interest to avoid that outcome.

“Yahoo has to do some kind of deal or Bartz will be facing a decline even she cannot manage,” said one person close to the situation. “And Microsoft, if it wants to compete in search, needs Yahoo’s share along with its own.”

Among the surprisingly innovative ideas being bandied about: Yahoo might take over all of Microsoft’s display and premium advertising business to sell along with its own, while Microsoft would run the search advertising business for the pair.

And, while the discussions could degenerate into chest-pounding and pointless jockeying, one assumes that Bartz gets the idea that Yahoo needs a lot of help–including from some rapprochement with Microsoft, from making its staff even leaner, from streamlining its product focus and from striking other significant partnerships.

Many inside and outside Yahoo certainly hope that spirit–and not the one from this video below of a fabulous scene of Betty Hutton and Howard Keel in the musical classic, “Annie Get Your Gun,” singing “Anything You Can Do”–prevails with Microsoft in the next 100 days.

Former Google (GOOG) exec Tim Armstrong officially started his job as new AOL chairman and CEO today and sent out a hello-there memo to the troops.

According to Armstrong, he is poised to “bring back the magic of AOL.”

BoomTown loves magic tricks and certainly hopes he can pull a rabbit out of the hat at the service, which was once the dominant player on the Web.

Armstrong is promising to look closely at AOL over the next 100 days, which “will end in Dulles with an All-Hands meeting in mid-July.” (Dulles is the Virginia-based AOL outpost that was once its world-wide HQ–it is now based in New York.)

There is homework too, AOLers!

But let’s hope it is not like the 100-day exam of Yahoo (YHOO) that did not work out so well for co-founder and former CEO Jerry Yang.

One sure sign of the seriousness of turning AOL around: While he has been getting ready to begin, AOL owner Time Warner (TWX) has been getting ready for Armstrong by putting in place conditions to allow AOL to spin out, seeking to amend debt agreements that restrict it from unloading the struggling business.

Here’s Armstrong’s entire memo:

AOLers -

Our work together starts today and we’re going to bring back the magic of AOL to our consumers and our partners.

As the world continues to move toward a digital information platform, AOL sits in a unique and venerable position. We’re a global digital brand and, thanks to your hard work, more than 275 million people across the globe touch AOL and our growing sub-brands every month. Billions of consumers and millions of businesses are making the digital migration, and we have a tremendous opportunity to help improve the experiences of all the people and companies making the transition.

We’ll make the decisions and the investments that are required to deliver exceptional value to our consumers. Consumers vote with their clicks and the time they spend on our sites, and we need to make world-class products and services that get votes based on a superior consumer experience. AOL’s partners and advertisers expect no less than our consumers, and we need to hold ourselves to delivering industry-best business solutions.

Over the next 100 days, I’ll be running a process to hear from all of you and many of the important partners connected to AOL. We’ll sit together in our offices around the world and have open forums about what we’re building for the future and what we’re accomplishing today.

The culmination of the 100-day process will end in Dulles with an All-Hands meeting in mid-July. At that meeting, we’ll review the feedback we’ve received–both internal and external. We’ll also discuss our strategic direction for the coming years, and highlight areas that will bring AOL and AOL properties into the next decade of digital leadership. Most importantly, we will set a course and focus all of our resources to make that course a success.

The road to Dulles in July starts this week with meetings in New York, Dulles and a Town Hall meeting with the team in Baltimore, and I plan to visit all of our global offices in my first 100 days. It is important for you to think about how AOL’s mission should be captured–how we can deliver exceptional value for consumers and partners, how we can encourage innovation, and how we can continue to make AOL an even better place to work. If you have thoughts before we meet, you can post them here and I will read them as we travel to all the offices.

Joining you today is a privilege and an honor. Over the past few weeks, I’ve had many opportunities to talk to current AOLers, AOL alumni and our partners. Each of them asked how they could help AOL revive the spirit we talked about in the tent in Dulles a couple of weeks ago–a spirit of dreaming big and delighting consumers every time they touch our brands. Jeff Bewkes and the leadership across Time Warner are putting their full support behind making AOL as successful as it can be. Now it is up to us to deliver on AOL’s full potential.

Thanks for having me and let’s set our sights high and our execution even higher. Go AOL.

- TA