Sometimes the assumption with "zero budget" marketing is that it's only for new / start up / tiny businesses. But every day huge businesses are looking for ways to cut their spend, wherever they can, if it's not delivering results OR if they have come across a smarter way to approach a marketing challenge.
In January of this year, the Procter & Gamble CEO advised 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. Yes, you read it right, $10 billion!
General Motors has recently followed suit in cutting their Facebook spend. That's two out of America's top three biggest advertisers. More on this here.
The two decisions were made for different reasons (GM isn't convinced Facebook ads are effective; P&G was seeking free media efficiencies) but they're linked.
It appears to be dawning on some businesses budgets that if your marketing content is interesting enough - engaging enough - you don't NEED to advertise on Facebook. Advertising on Facebook is can be free, if you can create something compelling enough to go viral. It goes back to ensuring your product, service - or marketing message - is remarkable.
Or put simply - stop shouting, start engaging with your market.