Microsoft does the "hush-hush" on Vienna

It seems that the rumours saying that by 2009 we'll have to do yet another OS upgrade were not right.

Guys over at ArsTechnica say:

When the "2009" story hit, we ignored the shipping date and paid attention to what was really interesting: hypervisors. Call me a pessimist, but I just could not believe that Microsoft would dare suggest that Vista's successor is only two years away.

I have to say that I think they are right. And to think that Longhorn launch date rumours back in 2004 stated that it will be on the shelves early 2005.
What are the rumour starters thinking? Or maybe they know more that us, the plebes.