When AOL parted ways with its chief marketing officer in December, both the action and the company's explanation for it -- a restructuring of the marketing department -- did not surprise close observers. The company seemed to be finding some necessary stability, but AOL under CEO Tim Armstrong has been a place where lasting more than a year in an executive role is far from a given and the rejiggering of business unit structures and titles has become commonplace.

Some of this can be attributed to the situation AOL finds itself in -- undergoing a turnaround attempt mostly unmatched in the internet age. Investors will be watching its progress toward that goal when AOL's fourth-quarter earnings are released this week. But on the other side of it is Mr. Armstrong, who moves at a pace all his own and who hasn't been afraid to mix things up.

Change agents, of course, are put in place to do just that. But despite all the change he's stirred, four years after Mr. Armstrong was poached from Google to spin off the "You've Got Mail" business from Time Warner and run it as a separate entity, AOL's path to growth is still unclear. The number of people who visit AOL properties has not increased in the past three years, and ad revenue, while mostly steady, has yet to show sustained growth. His two biggest financial bets -- local-news network Patch and the Huffington Post and its live-video network HuffPost Live -- have yet to contribute significant benefits to the topline.

The bright spot of late is the company's stock price, which rose 96% in 2012. A $1.1 billion sale of AOL patents as well as a large buyback of shares were big reasons for the bump. AOL's stock as of Feb. 5 is up 30% since it opened at $23.39 on Dec. 10, 2009, the day AOL shares were made widely available to the public. However, that doesn't include the $500 million or $5.15 per share returned to shareholders in a one-time dividend in December 2012. Including that dividend, total return from Dec. 9, 2009, to Feb. 5, 2013, was 52%, which beats the S&P 500 Total Return index, which gained 46% in the same period. Most Wall Street analysts have either a "buy" or a "hold" on AOL and the board last year extended Mr. Armstrong's contract through 2016.

But as Mr. Armstrong approaches his fourth anniversary next month, his work is cut out for him. Year-over-year revenue was flat in the third quarter of 2012 for the first time in his tenure, and Wall Street is expecting 2013 to be when AOL returns to growth.

Wooing advertisers
It won't be easy. AOL, which Mr. Armstrong reimagined as a media company post-spinoff, registered 110.8 million visitors to its properties in December 2009, his first year there. Since then, it's added Huffington Post and TechCrunch, but traffic remains relatively flat in comparison with four years ago; AOL properties notched 110.1 million unique visitors in December, according to ComScore.

"I'm the first one to say that flat traffic is not a win," Mr. Armstrong said last week in an interview at AOL headquarters. "But at AOL right now, it happens to be a win." His argument is that he inherited assets in steep decline -- among them, the email and Mapquest products -- and managed to keep traffic steady in spite of them. Growth, he said, is on the horizon.

The company's core revenue driver of selling advertising on those properties is steady, if uninspired. Ad revenue in the third quarter of 2012 was $340 million, off 15% from the third quarter of 2009, when the company still operated within Time Warner, but up 16% compared with the third quarter of 2010, when AOL was a standalone company.

Despite mixed results thus far, Mr. Armstrong is in good standing, both with the ad-buying community and Wall Street, surviving a distracting battle with an activist investor and -- despite some bumps along the way -- creating a setup in which he and another strong personality, Arianna Huffington, can coexist.

A salesman by nature, he can woo advertisers and close deals with the best of them. He has charisma that can rally the AOL troops around returning one of the greatest brands in internet history to prominence. And people generally like him -- partly because he is fun to be around and partly because of a do-good nature that manifests itself in charitable initiatives, which he pushes his company to partake in as well. "He probably has the best heart of any human being in this business," a former employee who reported to him said.

But the circumstances around the dismissal of the company's briefly employed CMO Jolie Hunt in December provide a glimpse into another side of Mr. Armstrong. In interviews with more than a half-dozen former execs, a portrait emerges of a passionate executive who can be demanding and exhausting to work for.

In the case of Ms. Hunt's departure, Mr. Armstrong originally said that AOL was decentralizing the marketing department, thus making an overall CMO role unnecessary. The company has followed through on that initiative, but it wasn't the whole story. People familiar with the situation later told Ad Age that disagreements between Ms. Hunt and Mr. Armstrong over the creative direction of an AOL TV campaign contributed to her exit after Mr. Armstrong became intimately involved in its direction. In last week's interview the CEO conceded as much, recounting what he told employees involved in the project.

Left brain, right brain
""I'm going to ask you guys to do something you've never done before. It's not going to fit into anything you worked on before,'" he said. ""It's going to feel tension-filled and I'm going to be on top of it. So if you think this is a normal ad campaign that's going to get done the normal way, this is not going to be the normal process.' I gave that speech many times up front. And I followed through on it."

Some point to examples like this as proof of a CEO who believes he can do most everyone's job -- sometimes better than they can. Those who've worked for Mr. Armstrong, including those who have left AOL on their own and those who have been asked to leave, say he's known to bombard his executive teams with ideas, prompting one industry exec who knows Mr. Armstrong well to proclaim: "Tim is the king of cocktail-napkin ideas."

"He has a great combination of left- and right-brain thinking," another former employee who reported to him said. "But sometimes that right brain can get a little crazy."

In the case of the TV commercial, Mr. Armstrong wanted to incorporate dancers and have the spot take cues from the 1990s rap hit "Mo Money Mo Problems." He also wanted to find every married couple that met via an AOL chatroom. Separately, Mr. Armstrong has been known to spend time dreaming up ideas for gifts for ad agencies and their execs, some of which he's been talked out of, and some that he has not. Among them have been gumball machines, motorized scooters and AOL-branded tracksuits.

The enthusiasm and velocity of his brainstorms presented a quandary for some reporting to him. Just because Mr. Armstrong says something doesn't actually mean he wants it to happen. Do you make sure you have the budget for it or just go full-speed ahead? Do you let him sleep on it or follow through right away?

"We had a three-strike rule with Tim," said another former AOL executive. "He had to ask you three times before you did it."

Mr. Armstrong does not shy away from these observations about his freewheeling and sometimes erratic creative spirit, though the pained look on his face listening to the feedback suggests he is hurt by some of it. He admits he finds creative inspiration all over. He talks about visiting a Nike store in Washington D.C.'s Georgetown neighborhood, snapping 100 photos to bring back to show the company's product team. In his early days at AOL, he says, he planted a bunch of Kidrobot figurines, which stand about two-and-a-half-feet tall by the looks of the one that still stands in his conference room, in random spots around the company's New York office to let employees know it was OK to have fun again.

"I'm used to being in creative environments where people throw out a lot of ideas," he said. "Sometimes people struggle with the [speed of the] idea generation. But if you compare it to some of the other places I've worked, it wouldn't be an unusual day. But I understand that feedback."

True Calling
Former executives understood his heavy involvement in sales and marketing. But many were surprised to find a CEO knee-deep in product launches. He presided over the AOL.com home-page redesign in 2010, leading some who worked on it to feel they didn't have a real say. But Mr. Armstrong, despite the acclaim he's received for creating and scaling Google's sales operation, believes his true calling is not in fact in sales.

"The reality is, I've started multiple companies, so actually I'm probably more of a product/creative person than I am sales," he said. "Although I can do both."

Speedy decision making has been another trademark. Too speedy, lamented several of his former direct reports who describe a leader who gave his executives three months to six months maximum to prove themselves before stepping in himself.

A couple of months after AOL launched the AOL Editions mobile-news app, for example, the tech team was notified that Mr. Armstrong was pulling resources because it had not yet showed enough traction, people familiar with the situation said. The company has had four PR leaders in the past two-and-a-half years, and three sales leaders in the past 18 months.

"My job is to make whatever changes we need to make to make the company successful and to make the employees successful," Mr. Armstrong said. "The No. 1 criticism most managers get is that they don't ever change or wait too long to make changes. ... It's very simple: Either things are performing or they're not. And if it's not performing, we have to make changes."

Mr. Armstrong waved in front of him a stapled packet that appeared to contain at least 20 pages filled with business metrics. "This is the level of detail that we go through all of the products and services," he said. "So trust me: When we're making decisions it's not that we didn't give it enough time to germinate."

There are executives who continue to command Mr. Armstrong's loyalty, even as their roles have shifted: Jon Brod, Patch's co-founder and CEO; Ned Brody, CEO of the Advertising.com Group; and Artie Minson, the CFO-turned-COO, who has been credited with slowing the loss of internet-access subscribers better than Wall Street expected.

And there's no denying that AOL under Mr. Armstrong has made some bets with a long-term view. On the display-ad front, he is championing Project Devil, large-format ads that advertisers can use to incorporate interactive elements such as image galleries, videos, and store locators. Mr. Armstrong said two of the challenges remain "getting systems inside agencies to focus on this" and getting advertisers to stop settling for engagement metrics that they see on less-dynamic formats.

Another long-term bet is Patch, the 800-plus local-news sites Mr. Armstrong helped fund and later acquired. AOL has said Patch was on track to generate $40 million to $50 million in revenue in 2012, though the company is said to have spent several hundred million dollars on it to get to that point. Mr. Armstrong has told investors to expect to see Patch reach profitability in the fourth quarter and analysts believe he will do whatever it takes to make that happen.

Jeff Lanctot, chief media officer at Razorfish, believes that Patch has been hurt by the resiliency of community newspapers and says he has shared this opinion with Mr. Armstrong. "It's a good strategy, but I think they are out ahead of demand," he said.

AOL does have momentum in other areas that make Wall Street analysts optimistic. Video revenue was expected to reach $100 million in 2012, thanks in large part to the smart acquisition of the 5Min syndication network in late 2010. Streaming-video network HuffPost Live is nothing if not ambitious.

And the Advertising.com Group has been trending up. The company hopes to be able to prove to investors that it should be valued higher when the company starts reporting more details about individual business units in its fourth-quarter earnings.

"It's really easy to throw stones around the lack of traffic growth or the monetization around the ad inventory or the fact that Patch still isn't profitable," said Heath Terry, a Goldman Sachs analyst. "But if you had bet anyone out there when Tim took over that AOL would be where it is now, there wouldn't have been a lot of takers."

For his part, Mr. Armstrong remains proud -- but not satisfied -- with where the company is today. Asked to grade the company's progress under his helm, he gives it an "A," considering the early hurdle of spinning out the company and the continuing battle to slow the decay of the legacy internet-access business. And he seems to get a certain amount of satisfaction in the demise of fast-growing media-darling startups such as Groupon, which have largely flamed out while AOL -- a longtime media punching bag -- has steadied.

"When I got here, many people inside the company and most outside of the company never thought it was possible to re-grow AOL," he said. "And I think that's the point we're at today."