Forget about the privacy concerns, the onslaught of ads, the annoying design of your profile page. If people are slowly turning away from Facebook, it's not because the company has overreached or gone over to the dark side.

It's because we've come to realize that people are boring.

Surely you've noticed this yourself, as you've scrolled through updates about vacations and restaurant meals, plus notices about how many of your friends are currently playing Candy Crush Saga.

A survey released last week by the Pew Internet & American Life Project found that 61 percent of Facebook users have taken a "Facebook vacation," for reasons that had little to do with how the company behaves. "Too busy" was the most common complaint, followed by "just wasn't interested" and "it was a waste of time."

"It's a reckoning moment," said Lee Rainie, the director of the Pew project. "People are making little mental calculations about how much time do I want to devote to this, what's the quality of the material I get from my friends?"

This is, in some ways, a significant milestone in our growing relationship with social media. Early complaints about Facebook centered on the fact that interactions were fake: hand-picked, overglossed, idealized personal statements that were bound to make your friends feel insecure, and vice versa. But now that we're all familiar with the Facebook mask, the problem might be that our posts are too real, and that reality isn't worth our time.

Earnest efforts to promote unplugging, such as the annual Screen Free Week, are gaining traction, and Facebook's policies have done their part to diminish our trust. But it turns out that our own inanity is also a powerful force.

Not that it's time to fear for Mark Zuckerberg's welfare. Facebook is used by a mind-boggling 67 percent of adult Americans online, including your mother, your father, your great-aunt Hilda, and your long-lost friend from high school with a political vendetta. The fact that we're now settling into a mature routine is actually a sign of how intertwined our lives are with our feeds -- and how much we feel an obligation to take part.

As much as I grumble, after all, I still feel compelled to dip into the Facebook universe every few days, posting photos of depressingly minor life events -- Attention, world! My child went to the dentist! -- or scrolling down the news feed and "liking" 15 items in one sitting. I'm marking my presence, like a dog. If I lay off the site for a few days, I invariably miss six birthdays and feel like a jerk. If I stay away for longer, I worry I'll miss big news.

Every new medium eventually finds its purpose. Twitter works great as a news aggregator and wisecrack-sharing platform. Pinterest is a gallery for home-decor ideas. Facebook has become the accepted repository for information about births, deaths, and traumatic family events. It's also reasonably good for mobilizing social movements and conducting virtual yard sales.

For photos of kids and vacations? Well, there's this nifty thing called paper. A few weeks ago, we finally took down our display of holiday cards, those cheery family photos that Facebook should have rendered obsolete. They still feel more valuable than the average digital post, precisely because they're worth the cost of bulk printing and a stamp, and because they require the physical act of opening an envelope.

Holiday cards are one of the last remaining things that we still instinctively send by mail, along with thank-you notes and the occasional party invitation. Right after the Pew Facebook study came out, the U.S. Postal Service announced that it was dropping Saturday delivery, prompting a flood of lamentations -- on social media, of course -- from people who may not have written a letter by hand in years. I, too, will miss the weekend mail, but it's hard to argue with reality. The other day, the sum total of my mail was an electric bill and a flier from Costco.

If someone sent you a snail-mail photo of his kids every day or every week, you'd think he suffered from a personality disorder. But holiday cards are an annual thrill, precisely because they come once a year. Looking for a new, Facebook 2.0 standard for how much we ought to share? It turns out we might have had it all along.