Chair-flinging Microsoft kingpin Steve Ballmer has continued his public campaign against Google, characterising the search firm's growth strategy as "insane."

The famously irascible billionaire, currently fourteenth on the Forbes' richest-yanks-on-the-planet list, made the remarks during a talk to Stanford Business School students on Wednesday. Ballmer studied there as a young man after a first degree at Harvard, but dropped out to work for Bill Gates.

Ballmer suggested that Google was growing too fast, and had failed to make a success of efforts to diversify beyond search with ads. He dismissed Google's various other projects as "cute" to chortles from the assembled business students, and commented that "a random collection of people doing their own thing" might not add value. This was taken by many as a jab at Google's well-known practice of allowing its engineers to spend 20 per cent of their working hours on personal schemes.

Wednesday's dig was mild and good-humoured compared to other episodes in Ballmer's career. The emotional exec reportedly required surgery after "blowing out his vocal cords" with repeated cries of "Windows, Windows, Windows" at a meeting in 1991, and "barked the word 'developers' 14 times until hoarse" at another function 10 years later.

The feud with Google is a long-running one, with Ballmer previously reported as shouting "I'm going to f—king kill Google" and "Eric Schmidt is a pussy" during a 2005 dust-up over an allegedly poached employee. He has also described Linux as communism.

Does the relative calm of Wednesday's episode mean the bad boy of Redmond is finally mellowing with age? Tech commentators worldwide will be hoping not. ®

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• Vista: Gates backs Ballmer against confused analysts (21 February 2007)
• Ballmer downplays Vista sales (16 February 2007)
• Ballmer: Microsoft helped security partners on Windows Vista (18 October 2006)
• How Microsoft can 'kill' Google (22 September 2005)
• Ballmer: 'I've never thrown a chair in my life' (13 September 2005)
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• MS Analysts MS' Ballmer: Linux is communism (31 July 2000)