I moved the last few boxes of my meager possessions out of my house today. Although the clock started on my separation period some time ago, today will be the first day in my new home. Until now I’ve kept my private affairs private. Although my neighbors have surely noticed me quietly moving boxes and furniture out of the house over the past few weeks, my conversations with them have never gone beyond the genial yet superficial banter of neighbors passing each other on the sidewalk. Similarly, my Facebook wall has been quiet. Since I have many mutual friends with my ex, I have tried to limit any signs of the implosion of our marriage, lest people prematurely began taking sides. I suppose that I want to be out of the house before this happens.

It has dawned on me, however, over the past several weeks, that Facebook—or at least Facebook advertisers—knew about my breakup long before everyone but my closest friends and family members. I know this because it was weeks ago that I began noticing the advertisements in my news feed for dating websites like Zoosk and Tinder.

“We know what you’re going through, Philip,” the advertisements seemed to say. “It’s never too soon to get back on the horse, so to speak.”

This revelation is nothing new. Others have already written about how Facebook knew a man was gay before he officially came out and how Target knew a teenager was pregnant before her parents found out. As a private investigator, I understand the subtle behavior that led these advertisers to target me. These are some of the same inferences that I might use as an investigator to figure out things about the people I’m investigating.

During my first divorce, some years ago, I did a little experiment. When I moved into an apartment down the street from the marital home, I decidedly didn’t change the mailing address with any of my creditors, instead just picking up my mail from my former address. Likewise, I didn’t change the address on my driver’s license or otherwise use the address for anything (except to sleep and feel sorry for myself). I then periodically did searches for my name and Social Security number using investigative databases to see how long it would take for them to figure out where I was living. I lived at this apartment for one year, and during this time the databases never reported where I was actually living. What this means is that, had I been a witness or a defendant and had an investigator been trying to locate me, they would have had a very hard time doing so. I was effectively off the grid, and it wasn’t altogether too difficult.

But my first divorce was prior to the prevalence of Facebook. Even for someone like me who’s much attuned to how seemingly innocuous information on social media can reveal troves of information about someone, it is nearly impossible to hide oneself completely in the Era of the Internet of Things.

In a case my firm recently worked we were hired to locate an elusive defendant whose most recent address was not available in any investigative database. However, she was an avid runner who liked to post the routes she runs on Facebook. Discovering that she had recently befriended a man who lived close to the area where most of her jogs began, we hypothesized that this was her new boyfriend and that she was staying with him. We turned out to be right.

Advertisers make the same types of assumptions about all of us every day, or rather they use complex algorithms that attempt to predict the things we may want to purchase. A woman who suddenly switches to a new brand of lotion, for example, or who changes her purchasing habits in other subtle ways may be pregnant, so cue the baby furniture coupons.

What attorneys and investigators should know is that leveraging the breadth of information available on social media—either to locate people or as evidence—increasingly involves thinking more like a computer than a blunt instrument. This is particularly true given that there is a trend toward the impermanence (sort of) and anonymization of some elements of social media, as evidenced by the popularity of companies like Snapchat and Whisper. Snapchat in particular, which allows users to send photographs to each other which then effectively self-destruct (unless the recipient does a screen capture), has become a bane for police investigators tasked with investigating underage sexting.

One way to better think like a computer is to understand how advertisers interpret your behavior and the behavior of other consumers to figure out things about you that few other people know. When you understand how that works, then you can use the same logic to glean similar information about the subjects who you’re investigating. What does the fact that a potential juror “likes” Wal-Mart on Facebook tell you about the likelihood they’ll be sympathetic to your client? How do you find someone online who primarily uses pseudonyms?

Should you want the answers to these and similar questions, please don’t hesitate to contact me. I’ll be at my new place just down the street (probably sleeping and feeling sorry for myself), which you might have already known had you been paying closer attention.