We keep hearing that Facebook's Sponsored Stories ads — the posts from advertisers that appear in your News Feed — are much more effective than Facebook's regular display (or "MarketPlace") ads. Sponsored Stories are the only ads that appear on Facebook's mobile apps, where most of its users are, too.

AdParlor CEO Hussein Fazal, one of Facebook's largest ad buyers, sent us this chart (below), which dovetails neatly withdata we published earlier from a rival Facebook client. The chart shows the relative effectiveness of Sponsored Stories vs. Marketplace ads on Facebook. Fazal says, "Since Q1 2012 we have been driving more fans using Sponsored Story ads than regular marketplace/inline like ads for large brands and agencies. This data covers millions of fans we have driven."

He declined to tell us what the y-axis scale is — big caveat! — but still, Sponsored Stories is where the action is for big clients on Facebook right now (click to enlarge):

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