Facebook Experiments With Another Mobile Answer: Ads You Didn’t Ask For

Facebook says it has figured out a way to sell mobile ads, but that doesn’t mean it is done experimenting. The newest test: Some Facebook advertisers will now be able to place “page posts” in the news feeds of people who aren’t their fans.

What that means: Up until now, the only way for most advertisers to get onto a Facebook user’s phone was by paying for a “Sponsored Story.” Those appeared in your main newsfeed, and if you saw them, it meant you were looking at a product or brand that you had already liked, or that one of your friends had already liked.

This shift removes that hurdle. So if Facebook makes it a full-blown option, it will open up a lot more mobile ad inventory for Facebook (ditto for regular desktop ads, which will work the same way).

Unless Facebook goes nuts and opens up the floodgates, it’s doubtful most users will be able to tell the difference, since the ads will look exactly like the “page posts” for stuff they’ve already liked, and not much different from the “Sponsored Stories.”

If you take the time to think about it, you may notice that the ad says “sponsored,” and that none of your friends have liked the thing in the ad. But odds are you won’t.

But the experiment is a change from the philosophy Facebook was espousing in the spring, when it was selling advertisers on the idea that the best way to advertise on Facebook was to get Facebook users to do the advertising, by sharing and liking their stuff.

It’s also the second deviation from that idea that Facebook has tried this month. Last week, the company announced that app developers could pitch their stuff to mobile users using specially designed ad units, which also didn’t need social hooks to show up in the main feed.

Why the switch? Facebook isn’t saying anything beyond the fact that it’s just testing the idea out. But look at what CFO David Ebersman said last month, during the company’s first earnings call:

Ad impressions continued the recent trend of growing more slowly than users as more of our usage is on mobile devices. This trend is particularly true in markets such as the U.S., where smartphone use is expanding rapidly. The overall number of ads delivered in the U.S. this quarter decreased 2% year-over-year despite a 10% increase in daily users and despite the increase in ads per page from the product changes I mentioned earlier, as daily Web users in the U.S. declined in favor of mobile users. And we’re seeing similar trends in other developed markets.

Translation: We’d like to sell more ads, but that’s hard to do when everyone’s logging in on their smartphones. So this should make it easier.

This is also a whole lot more conventional: Google would like to know if your friends like a product, but they’ll show it to you regardless. Twitter is headed this way, too. Facebook is already selling $3 billion worth of ads a year. But joining them couldn’t hurt.