Glyn Moody hits the nail on the head with his critique of Microsoft's proposed approach to Windows 7: Say little so that the market expects little.
It's not an unreasonable approach, and Microsoft did get burned for actually warning the market about what it would be providing, only to have to endure the consequences of not living up to the expectations it set, but I'm not sure it can afford to go back. Stating that it will be "more careful" with Windows 7, Microsoft's representative noted:
"We know that when we talk about our plans for the next release of Windows, people take action," [Microsoft] said. "As a result, we can significantly impact our partners and our customers if we broadly share information that later changes."
Well, yes. But that's the whole point behind transparency. As Glyn notes, it's not that easy to do in practice, but it's increasingly critical in the opening 21st Century.