Project Mojave was a focus group where Windows XP users, who hadn't upgraded to Windows Vista were brought in, interviewed about their perceptions of Vista and then they got an exclusive demonstration of the next release of Windows, code-named "Mojave".
Of course the kicker is that the product being demo'd wasn't "Project Mojave" it was Windows Vista!
Of the 140 respondents polled (on a scale of 1:10 where 10 was the highest rating), before they saw the demo, the average rating for Windows Vista was 4.4 after it was 8.5.
They've upgraded the site and added the actual demos that were used. It's worth a visit to see the reactions alone!
[By the way, contrary to what's been written, the PCs used to demo Vista were not specially built super computers, they were off the shelf, you can find out more at the site.]
More from the Windows Vista blog.