magnifying glassLast year, Facebook started running ads that used your Web surfing history to target you. Soon they’ll be a little more obvious about the fact that they’re doing it.

But not a lot more obvious.

After months of discussion with the Council of Better Business Bureaus, Facebook is going to start incorporating a small triangular “AdChoices” logo on some of the ads where it uses “retargeting” — the common Web practice of serving ads to surfers based on the sites they’ve already visited.

If you have a sharp eye, you may have seen the triangle on lots of other Web sites, including those run by Yahoo and Google. That’s the result of a self-policing move Web publishers made a couple years ago, in an attempt to keep privacy watchdogs and Federal regulators off their backs.

Here’s what it looks like, for instance, on an ad running on Yahoo’s home page today.

yahoo adchoices

In theory, when you see one of the triangles, you can click on it and learn more about a given Web publisher’s targeting practices. And then you can opt out of them if you want (here’s what happens if you click on Yahoo’s triangle).

In practice, I find it hard to believe most consumers notice the icons at all (that text looks a whole lot smaller when it’s side by side with everything else competing for your attention on a Web page). Or that they’ll understand the language they’ll encounter if they do click on them (“The Web sites you visit work with online advertising companies to provide you with advertising that is as relevant and useful as possible,” etc.)

In any case, Facebook is going to start using the same icons for some of the ads it serves up on the right side of its home page, where it has begun selling retargeted ads through its Facebook Exchange program.

Except you won’t see them unless you look for them, by hovering your mouse over the ad and clicking on the grey “x” that appears when you do. And Facebook doesn’t plan on using them on all of its retargeted ads — a Facebook rep says the company will only do so when its advertisers or ad tech partners choose to use them.

If that doesn’t sound like a lot, it’s at least an improvement over the current set-up. Right now, the only way you can learn that you’re seeing a retargeted ad is if you mouse over the ad, click the grey “x” and then click on the “About this ad” option.

If it turns out you’re seeing a retargeted ad, you’ll see a page that may or may not explain what you’re looking at. Here’s one I found today, from retargeter Chango, after clicking on a Dish Network ad.

If you care and know about this stuff, you’ll understand what you’re looking at. If not …

Which brings us back to the eternal “who does care about this stuff” question.

As The Wall Street Journal has documented via its excellent “What They Know” reports, the Web ad guys know a ton about you (so do the offline ad guys). And if you tell a normal person about it, they’ll get a little creeped out. They’ll also tell you that they think privacy is really, really important to them.

But in practice, this doesn’t seem to be an issue that galvanizes regular folks. And it has yet to find a powerful political ally — you didn’t see anyone running on the “I took on the cookie people” platform last fall.

Maybe that will change, and Facebook and its peers will have to be a lot more obvious about this stuff — or even ask consumers for permission before they go about doing it.

But for now, this seems like it will be enough.

By Peter Kafka