The ad on Facebook made this pitch: Sign up as a fan, and Best Buy will give you $1,000 to buy electronics. Instead, clicking on the "gift card" offer is really about surrendering personal information and inviting spam from marketing companies.

Bogus gift card deals have popped up so much on Facebook lately that they triggered a federal fraud alert. The scammers are posing as any number of big companies offering non-existent gift cards.

Best Buy spokeswoman Erin Bix said the company has been fighting these scams on Facebook and Twitter. Best Buy's legal team is hunting down impostors, while employees in its online "twelpforce" answer customer queries.

The bottom line: No company would pay a thousand bucks for a Facebook fan.