More than two decades earlier, the 1986 ad for Microsoft's first version of Windows looked more like an ad for Lowes or a home shopping item than a software product, with Ballmer shouting into the camera for a full minute. In the intervening years, Ballmer's crazy cheerleading behaviour has amused geeks the world over, and there are countless YouTube videos showing him up on stage screeching, shouting and performing his trademark "monkey dance" and "developers, developers, developers" chant. "It's almost like an evangelist movement when he's up there and you can imagine a few Hail Marys and the like being thrown in. It's got that sense to it," said Dr Peter Langford, a senior organisational psychologist with Macquarie University. Ballmer's constant gesticulating, tongue-poking, finger-pointing and various outlandish facial expressions during speeches have quickly made him a photographer's favourite. He even popped out of a cake at Microsoft's 25th anniversary celebrations.

Langford, who specialises in corporate culture and leadership, examined Ballmer's unbridled enthusiasm and concluded that, while it's definitely bizarre, it was most likely a deliberate performance. Ballmer, Langford believes, wouldn't have lasted for more than 30 years at the top of a $US200-billion software company if he was genuinely insane. "It [his behaviour] is unique to CEOs, but not so if we compare to some entertainment celebrities, motivational gurus or evangelists," Langford said. "He's building a celebrity status for himself and Microsoft. It is important that CEOs are larger-than-life and this is his way of doing that." Ballmer's shoot-from-the-hip style has also been a boon for journalists, who have lapped up incidents such as the time he reportedly threw a chair across his office.

Former Microsoft employee Mark Lucovsky said in a sworn court statement that Ballmer said of Google and its chief executive Eric Schmidt: "I'm going to f...ing bury that guy. I have done it before and I will do it again. I'm going to f...ing kill Google." Ballmer has also described the free Linux operating system, which competes with Microsoft's Windows, as a "cancer that attaches itself in an intellectual property sense to everything it touches". In 2004, he said the most common format on Apple's iPod was "stolen". Ultimately, Langford said, Ballmer had been able to get away with a lot of his behaviour and maintain an endearing persona because Microsoft had continued to perform so successfully and produce compelling products. "If Microsoft was to come out with another Vista-like product and continued to lose ground in the areas of browsers and search engines, then I think people would be saying that he's a buffoon, he's a fool, look at how he's performing on stage," Langord said.

Langford noted that Ballmer appeared to be far more reserved when speaking to foreign audiences such as Indians. He said he could probably pull off his character better in the US than he could in Australia or Europe because Australians were "a little more sceptical and distrustful". "An act doesn't mean that it's false. It's just he's got that capability to hype up when he wants to or when he thinks it's appropriate," Langford said. But he said there was a risk Ballmer's antics could be seen as unstable or unethical, which might cost Microsoft in the post-Gates era. Loading

"He's clearly got a very different style to Bill Gates ... but Bill Gates has a guru aura without having to perform like that," Langford said. "Bill Gates is seen as the guy who started and grew Microsoft and he was a legend in his own right. He didn't have to hype it up to grab the attention."