Facebook is collecting data on its latest ad units by asking for direct user feedback through the question, “Which of the above ads do you prefer?”

We saw Facebook conducting similar research in February 2011 among users in Israel. This was before the rise of Sponsored Stories and ads that come from page posts, as seen to the right. Now some U.S. users are seeing the survey, which presents three multiple choice options: neither, top ad or bottom ad. Previously, Facebook did not offer the “neither” option. The survey question appears in the right sidebar underneath two ads.

The social network has implemented a number of new ad units over the past year and a half, and advertisers are increasingly choosing these types over the traditional ads with a headline, body copy and image. There is plenty of quantitative data Facebook can collect by serving billions of ad impressions a day, but this type of research poll helps the company gather how users feel about different ads on the site. If Facebook finds trends — for instance, users prefer photo ads over question ads — it can reconsider whether it should redesign the ad unit or get rid of it all together.

There is also opportunity for Facebook to apply research poll data on an individual user basis so that ads are more personalized, similar to how the social network tailors News Feed to each user. For example, it might become clear that a user prefers ads for consumer products over enterprise software. This could help Facebook show users the ads they are more likely to click and take action on.