We have two ads to drive page likes.
First, one promoting a T-shirt giveaway:
And another page like sponsored story (an ad unit going away on April 9th):
Clearly, the standard newsfeed ad is much bigger.
But the page like story actually had a higher CTR (barely).
The cost per fan was only 77 cents on the contest, while the sponsored story was $1.08.
But contest fans are generally of lower quality, since they just want to win, not become customers.
Both are bid at optimized CPM, where Facebook is choosing what subset of users to show the ad, plus at what price.
But the sponsored story was a significantly higher CPM– $18 vs $13 in the newsfeed.
Who do you think was the winner or what else would you need to know to make decision?