• by Wendy Davis , Staff Writer @wendyndavis, March 26, 2013

In an expansion of its online advertising efforts, Facebook announced today that it intends to place retargeted ads directly into users' news feeds.

“Allowing advertisers to reach people in News Feed is important because people spend more time in News Feed than any other part of Facebook,” the company said in an announcement about the new initiative. For now, Facebook is working with the demand side platforms TellApart, MediaMath, and Nanigans. The company says it intends to expand soon to other demand side platforms and advertisers.

Retargeting in itself doesn't pose any unique privacy issues -- at least compared to other forms of targeted ads. And Facebook apparently intends to let people opt out of receiving retargeted ads. But the company probably still can expect a new round of complaints from users who think their data is being misused.

That's because retargeting draws on data in a way that's far more obvious than other forms of behavioral advertising. Retargeting involves sending ads to people based on their activity on an e-commerce site -- often for the very product they were viewing on that site.

For instance, people who view a watch at Hautelook.com, could then receive ads for that same watch, from the same site, directly in their news feeds.

That type of targeting is far more transparent to users than other forms of behavioral targeting. Consider, people who are served a car ad one day after reading an article about new cars might not know whether there's a connection between the ad and the article. But when companies use retargeting, it doesn't take much detective work for users to figure out that they're receiving ads from a merchant they recently visited.

At the same time, because it's obvious that retargeted ads are based on tracking data, the technique seems to highlight privacy issues. Given Facebook's dismal record on privacy, it won't be surprising to see a backlash from these ads.