The advertising campaign promoting Microsoft has hit a new low. And no, we don't mean another pointless, rambling commercial about nothing.

According to metadata dug up by Flickr user LuisDS, the "I'm a PC" ad campaign images were made on a Macintosh.

What's that sound? It's the sound of a million Mac users, laughing.

So how should Apple respond?

- Ignore it as being beneath their attention, like the Zune?

- Riposte it with some cunning counter-counter-campaign? (Image: "I'm a PC" advert plays, camera pulls back to reveal the ad being edited in Final Cut Pro.)

- Will they, having fooled Microsoft into trying to mirror their success with fact-free advertising, suddenly launch into a technically detailed series of tour-of-Leopard ads?

- Go meta and start a campaign of adverts about the adverts. ("Hello, I'm a PC advert" "And I'm a shrink.")

What do you think Apple's next advertising move should be? Drop your ideas in the comments below.