Facebook Display Ads On Third-Party Sites? It’s Already Doing It For Facebook.com (On Google’s Network)

There has been some speculation about when Facebook might launch an advertising network to run on sites apart from its own, using its trove of data on what its 845 million users like and share.

But while the company has been silent on whether it plans to do this, it has also quietly moved into display ads in the wider world of the Internet — via a series of ads for Facebook itself. And one of its ad network partners, ironically, has also been one of its biggest competitors: Google.

Facebook’s ads on Google’s AdSense network — brought to our attention by a tip from a reader — have been live for about six months already, TechCrunch understands, as part of a bigger display campaign running for the past couple of years (one other sighting here from Josh about a year ago).

At this point, it looks like those ads are only for Facebook itself. Yes, they’re being run to further boost their 845-million monthly active user base. But possibly also just to remind those who are registered to keep logging in and interacting.

The ads we’ve seen are fairly basic: one is aimed at encouraging visits to Facebook “find & connect with friends”; another touts the “1,000s of games” on the site. And occasionally, those ads are being run alongside Google’s ads for its own Google+ social network:

But those AdSense ads also serve as a reminder of another route Facebook could take when/if it does decide to launch a larger ad network. It could do so as a third party on another network, like AdSense, as other ad networks do.

To be clear, Facebook is not an ad network partner for AdSense right now (this is the list published by Google). And there are pre-existing ad complications between Facebook and Google that might need to be revisited in any event: in March 2011, Facebook told its developers that they could no longer use AdSense ads in their apps, because Google violated some of Facebook’s terms on data usage. One year on, it looks like Google still has not made it to that list.

In a more general sense, running display ads via a third-party network could be a useful way for Facebook to test the waters for a deeper display strategy, making more use of the social data it has been collecting from third-party sites with its like buttons and other engagement levers. It could also be a good half-way move to calm reservations from those who, as John Battelle notes, worry about the “creepiness factor” of Facebook moving into a more comprehensive social display advertising business.

Facebook and Google are nearly neck and neck when it comes to display advertising revenues at the moment. But eMarketer believes that this year Facebook might just overtake Google in display revenues — at $2.58 billion for Facebook versus $2.54 billion for Google. Longer term, however, it predicts that Google will be the bigger player.

The display ads that Facebook is now running complement the investment Facebook has made in other external online advertising, primarily in the form of search ads. Those have run not just with Google but other large search engines like Bing and Yahoo, and capitalize on the fact that “Facebook”  is one of the most searched-for terms on those sites these days.