A strong user base is key.
A Flight Simulator enthusiast wrote up some notes about the new version (titled "Microsoft Flight Simulator X") as caught by Susan (Engauged) in her post:
Some more entertainment
The same user is back. This time with a post (from Avsim) on the potential timing of a holiday release for FSX:
Release date of FSX in conjunction with perspectives from Astrological timing
Now go back and read the Guy Kawasaki post about product eveangelism