According to the polling firm's latest "State of the American Consumer" report, released Monday, just 5% of Americans say social media advertising has a great deal of influence on which products they buy. In fact, 62% of the 18,000 people Gallup surveyed said social media advertising has no effect on their purchase decisions at all.
The polling firm says consumers are much more influenced by offline interactions with brands, like retail display windows and in-store visits, than social media.
The report will almost surely raise eyebrows at Facebook and Twitter, to say nothing of the brands that will spend a combined $11.4 billion advertising on the two platforms this year.
According to Gallup, Americans come to social media sites to interact with their friends, not brands, and have learned to tune out the advertising messages they come across.
"These channels do not motivate prospective customers to consider trying a brand or recommending a brand to others," the report said of social media. "Therefore, if companies want to acquire new customers, their best bet is to engage their existing customers and inspire them to advocate on their behalf."
One issue with the Gallup report is that it is based consumers' responses to survey questions rather than their actual behavior. It's entirely possible, if not probable, that social media ads influence people's shopping decisions without them even noticing. After all, they don't call advertisers "The Hidden Persuaders" for nothing.
Indeed, major web advertising companies like Facebook and Google have spent a great deal of time and money tracking consumers in hopes of proving, definitively, that their ads persuaded people to make purchases.
And other research, like an October study from Adobe, suggests that social media ads are, in fact, effective.
In order to make social media work for brands, Gallup says companies should focus on engaging with their existing customers rather than pursuing new ones. Additionally, the report says, brands need to make sure the content they post feels authentic and is compelling enough to capture consumer attention.
"The process may involve a lot of trial and error, but there is potential in social media that is not directly related to sales revenue," the report said. "Companies have an opportunity to build communities with their customers in ways they could not before. But to get there, they must first engage their customers through other channels."