Scream

General Motors' decision to cancel the entirety of its $10 million Facebook ad budget is, arguably, the second major shoe to drop on the social network's ad budget.
Back in January, Procter & Gamble CEO Bob McDonald told Wall Street he was scaling back his company's $10 billion annual ad budget (mostly in traditional media) to take advantage of free impressions offered by Facebook in the form of Likes and status updates.
That's two out of America's top three biggest advertisers.
The two decisions were made for different reasons (GM wasn't convinced Facebook ads are effective; P&G is simply looking for free media efficiencies) but they're linked.