There's a great BusinessInsider article about how Facebook has recently begun focusing heavily on retargeted ads. The crux of the story is this: The holy grail in advertising is knowing a user's "intent," because if you know what they intend to do, you can influence their behavior through advertising. Facebook has been working for years to discern "intent" via a complex formula that creates a social graph for each user, with big data mining algorithms that seek to divine what a user will be interested in based on that graph, so ads can be targeted in real-time to those users.

And instead, what's proving best at monetizing off "intent" is good, old-fashioned ad retargeting, which Facebook has recently started doing.

What struck me is that for the first time in years, a Facebook ad recently caught my eye. And it was a retargeted ad.

I've recently been shopping for a good camera. Not a huge, hulking DSLR camera like the pros use, but something that's a big step up from a point-and-shoot. After doing a bunch of research, I settled on the Panasonic Lumix GX1 camera for a number of reasons which I'll outline in a future blog post.

And then yesterday, when I was on Facebook, I saw an ad for a competing camera, the Sony NEX 5n. I was drawn to the ad immediately, because I had almost chosen to buy that camera. Needless to say, the ad was much more effective than any other ad Facebook could have run, and there's no way Facebook would have ever known my "intent" -- that I was shopping for a camera -- via its complex social graph algorithmic approach. I didn't tell any 'friends' I was shopping for a camera, for instance.

If you're not familiar with ad retargeting, you can learn more about how it works via this Wikipedia article. It involves placing a cookie on your browser that indicates you've visited a vendor's website, and then allowing that vendor to serve you ads across other websites (and now, within Facebook) to try to bring you back.

Retargeted ads have been around for a long time, but surprisingly many people don't know how they work, and don't use them. If you're an e-commerce vendor trying to battle abandoned shopping carts, retargeted ads can be especially effective.

And so there it is: A 10 year old ad technology is what's working best for Facebook. Maybe we should all keep Occam's Razor in mind in the tech world: In this case one of the simplest ad technologies is turning out to be the most effective for Facebook.