First it turned out that the new Microsoft ads were made on Macs, now it turns out that the celebs are Mac Users

Apparently, even the biggest companies can make some serious marketing blunders.

Microsoft's "I'm a PC" advertising campaign was created on a Mac and the celebrity spruikers brought in by the software giant are all professed Apple fans, it has been revealed.

Hidden information contained in images from the ads published on Microsoft's website show they were created on Macs, a Flickr user revealed in a published screen shot.

Microsoft responded by quickly scrubbing the hidden "metadata" information from the images. . . .

But even though a third ad featuring Seinfeld was filmed, Microsoft dumped the comic last week in favour of new ads featuring more current celebrities such as actress Eva Longoria, singer Pharrell Williams and even author Deepak Chopra declaring "I'm a PC".

But all three are Mac fans, Silicon Valley gossip blog Valleywag revealed. Longoria owns a MacBook and Williams carries an iPhone encased in gold, while Chopra, in a column on nuclear weapons published in the Huffington Post, said it was "good to sell more iPods" as they were "entertaining and harmless".

Seinfeld used a Mac in the apartment he lived in on his namesake show and has even appeared in an old Apple "think different" ad. . . .