"In short, Microsoft informs computer shops that if
they put some Vista advertising in their newspaper advertisements
(or other forms of ads), there will be money in the bank for them,
paid in the form of marketing money from Microsoft.
"This is how Microsoft gets all those Vista advertisements all
over the place, including big OEMs. They pay you for it. It’s
an advert, not a sincere recommendation. This may also explain why
Dell’s adverts for Ubuntu-powered PCs are accompanied by
pro-Windows messages, as Ken Stark pointed out recently (Dell was
subjected to bad and exclusionary deals before)."