In space, they say, no one can hear you scream. Some marketers feel the same way about Facebook.
The social network has come to play a vital role for many of the million-plus businesses that promote their brands and connect with customers on its site. But it's clear that some marketers no longer see Facebook as their friend.
A recent post on the site by Eat24, a food delivery service, was the latest sign of marketers' discontent. The problem, Eat24 and others say, is that Facebook's algorithms that determine which posts appear in users' News Feed are unpredictable, and they're increasingly weighted towards those who pay to promote their posts.
"We give you text posts, delicious food photos, coupons, restaurant recommendations ... and what do you do in return? You take them and you hide them from all our friends," Eat24 said in a "breakup letter" to Facebook.
"It makes us think all you care about is money," Eat24 wrote, and promptly deleted its account from Facebook.
The social network won't be crying over the loss of one customer, but it points to a larger challenge for the site: As more businesses advertise on Facebook, it has to find a way to display their posts in users' News Feeds, which often are already crammed with posts from hundreds of friends.
But it has to do so in a way that won't alienate people by making them feel bombarded by marketing. And it needs to strike the right balance with what most people join the site for in the first place -- to connect with their family and friends.
One of the main vehicles for companies to promote their products and services is Facebook Pages. For free, they can set up a page and try to get people to visit it, often by generating likes.
But it's not easy getting people to "like" your page. Some marketers do it unscrupulously, by paying "click farms" that hire thousands of people, often in developing countries, to click on their posts. Facebook prohibits that, and will punish businesses if it catches them doing it.
Another way is to pay Facebook to make posts appear higher in News Feeds, or to promote Pages with advertisements. Many businesses do that, but it's an area where discontent is brewing. Marketers say the likes generated through those programs aren't as valuable as in the past, because Facebook's algorithms have dialled down the visibility of their Pages.
Some see it as a bait-and-switch tactic. It's like selling a billboard under the premise that a certain number of people will see it, and then parking a bus in front of it, said Jessica Canty, owner of Jake's Coffee and Espresso in Staunton, Illinois.
Sign up for CIO Asia eNewsletters.