For businesses trying to reach customers and potential customers online, Facebook, with its more than 1bn users, has become a platform that can’t be ignored.

And what’s better than a platform with 1bn users? A platform that, up until now, has been largely ‘free’ to market on.

But thanks in large part to the pressures it faces as a publicly-traded company, Facebook is becoming less and less free to companies looking to market themselves to consumers. And as detailed by the Wall Street Journal’s Sarah E. Needleman, the company’s increasingly aggressive efforts to generate revenue have some businesses rethinking their relationship with Facebook.

Bait and switch?

With Facebook pushing ad offerings like Promoted Posts, business owners who thought that their Facebook Pages were owned media are learning the hard way that using the world’s largest social network to drive sales can be an expensive proposition.

Case in point: Needleman cites business owner Richard Bishop, who estimates that he’d need to spend at least $9,100 each year to promote his 35 weekly Facebook posts to the 1,500-plus fans of his company’s Facebook Page. “All of a sudden they’re saying a minimal percentage of your fans will see your posts unless you pay. They devalued the value of a fan,” Bishop stated.

Another displeased business owner, Lindsay Gonzales, told Needleman that she tried Promoted Posts, but called it a “waste of money” because she still had no control over whom Facebook exposed to her posts.

It’s all about ROI, if you can measure it

Bishop and Gonzales are almost certainly not the only business owners who feel that Facebook has pulled the rug on them, but not everyone is upset aboutpaying for what they thought was previously free, however. Needleman points to restaurant owner Joe Sorge, who says he’s spending approximately $1,000 a month on Promoted Posts. And according to Sorge, sales are up.

Just how Sorge has tied his spend on Promoted Posts to higher sales is not described, and it may not matter as far as Facebook is concerned. So long as businesses believe they’re getting extra mileage from their Promoted Posts, they’ll consider the investment worthwhile. According to Facebook, use of Promoted Posts is up significantly, indicating that, at least for the time being, there are enough advertisers willing to believe.

But Facebook shouldn’t assume that this will last forever. It was far easier for business owners to ignore the soft costs associated with their Facebook efforts than it will be for them to ignore the hard costs imposed by Promoted Posts and other paid offerings. To build a base of loyal customers similar to that of Google, Facebook will realistically need to make it easier for advertisers, particularly those less sophisticated, to tie their Facebook spend to sales. And if history is any indication, that’s not going to be easy.