And as Scissons points out, the problem isn't very likely to be Facebook. It's the pages themselves.
Most brands are tired, driven by managers who either aren't engaged themselves or try to force engagement on others. Some have told me that they feel like they have to. If they can't demonstrate a steadily increasing number of customers jumping through hoops, their bosses or accounts start to think that they are failing or, more commonly, something else is.
How to maintain engagement without over communicating.
When engagement falters, chances are the people who liked it are suffering from brand fatigue. They might have brand fatigue because of under or over communication. And good network managers ought not to sweat it.
It's during these slower times that managers can reassess what they are doing and whether it is still aligned with the mission of the company and stated objectives of the network presence. They might also think like humans too.
Social media has an oddity about it in that even those people who play at calling for human businesses tend to forget they too are human. They start thinking of themselves as tribal leaders, experimenters, or even shepherds. They see their jobs like playing a video game, one that requires them to rack up numbers that no longer have names like Bill and Ted and Sally and Hannah. Instead, they have a bunch of followers, fans, or whatever labels happen to be assigned to their circles.
If you've ever worked in social media, you know it's true. But you can see it as a consumer too. If the brand thought of you as Bill and Ted and Sally and Hannah, then they would already know how engaged you may or may not be. They might appreciate that talking about toothpaste isn't an activity you intend to do daily. And you can't bring yourself to like every post or comment and make a purchase during every sales event. It's just not humanly possible.
How to rethink engagement on consumer terms.
Good network managers don't seem to have as many challenges. There are a number of pages that almost always seem like they are on a steady incline in all areas — reach, engagement, and promotion. Generally, these are managers who appreciate engagement and influence aren't measured by the number of likes, shares, or retweets.
Engagement is a two-way street — like real friends with mutual interests. Even if you don't see them for months, you can always pick up where you left off as if nothing ever happened. Ergo, we might "like" the page of a hotel before we stay there but don't need engagement from such a page as much as we just want to know it still exists the next time we fly into the same town. Maybe engagement sometimes simply means you're easy to find when you're needed.