The honeymoon is over. (Noah Kalina/AP)

Last week my colleague Joel Achenbach quipped that he could tell Facebook’s wave had crested because he thought it might be a good idea to buy some shares, and that was traditionally the kiss of death.

But of course we were invested in Facebook. That’s where we store all our memories. We were as invested in Facebook as you could possibly be without actually buying a share.

Even The Post played into this. Last weekend, we inquired, What does Facebook’s value say about ours?

If Facebook is a flop, what are we?

One of the reasons I wanted so badly for Facebook to succeed was that it would go a little way to justifying the bulldog’s lifetime I’ve spent on the site. It’s considerable. If I had back all the time I’d wasted on Facebook in the past few years, just think of all the YouTube videos I could have watched.

Is it a tech bubble? Tech bubbles are like baggage carousels — they sound much more fun than they actually are. In fact, ever since Lawrence Welk went off the air, bubbles have been somewhat frowned upon.

Perhaps, for Facebook the writing was on the wall.

Have you seen a study, ever, that said something like “Facebook is bringing us closer together, and people do not regret the time they spend on the popular social networking site”? No. All the recent studies about Facebook have found that a) it is implicated in divorces, b) it is linked to loneliness, depression and compulsion, and c) it is vastly annoying. That last one wasn’t a study, just an observation. Now we also have that creeping sense that it will go the way of MySpace, and all the kilograms of writing about What It Means To Like and the Tao of the Status Update will wither into dust.

The more you look at Facebook, the less it sounds like something you would want to invest in. It’s a divorce machine full of isolated, compulsive, near-strangers, all tapping away in the dark.

Gee, I’ll pass. What’s Twitter up to?

“Here is a captive audience to whom you can advertise,” Facebook says. “Once we figure out how to monetize it, it’ll be great.”

But the more you study the canonical Facebook user, the worse it gets. He is not the hip, photogenic, effervescent individual that all those status updates and images portray, but rather a sad, lonesome person best described as “the exact demographic who cries during 3 a.m. commercials for magical sponges.”

The people who Like most often, Larry Rosen found, are compulsive maniacs. Children and teens who spend too much time poring over the status updates of others on the site grow depressed and feel inadequate. Possibly, Facebook also helps wreck marriages. A U.K. Web site, Divorce Online, claims that Facebook appeared in more than one third of all divorce filings last year.

Now we are beginning to see the problem.

I am not saying that Facebook users are not a widely desirable demographic from whom much money can be made, but generally the only advertisers who buy into this niche market are selling value packs of catheters.

Maybe no one wants any part of this.

With all the proliferation of ego-data, we have been long laboring under the misconception that all of these numbers, somehow, mean something. Here are my numbers, you say. I know exactly how many people on this green earth are willing to stake an interest in me. Surely, this is valuable. Isn’t it?

Turns out all the time and effort we spend on Facebook isn’t worth as much as we think it is.

I could have told you that.