“Why do you buy advertising on Facebook?”

That very simple question was asked to marketers in a survey from Ad Age and Citigroup. The respondents were given six different reasons; build brand awareness, drive traffic, build fans or “likes,” stay in touch with customers, generate sales leads, and social commerce. They were then asked to rank those responses on a scale of 1-6, with 1 being most important and 6 being the least important.

What do you think was the most important to marketers? If you said generating “likes” or “driving traffic” you’d be wrong.

By an astounding margin, advertisers said that building brand awareness was the most important reason for them to buy ads on Facebook. Out of nearly 500 respondents, 45.9% ranked it as their top priority. The aforementioned “driving traffic” came in second with an average place vote of 2.89.

Check out the chart below:

As you can see, social commerce came in dead last.

Ever since the IPO, Facebook advertising has been a hot topic of conversation. Multiple reports have suggested that many advertisers are souring on paid Facebook ads, some even saying that free promotion (by running a page) is really all that the network is good for in their eyes.

But just today, one analyst projected that Facebook’s mobile ad revenues would jump to $300 million+ per quarter within the next year, and that they would surpass desktop ad revenues.