Facebook, Instagram, Pinterest and other social networks have spent more than a year rolling out Buy buttons that enable consumers to buy directly on their platforms. But few retailers are using the buttons, and even among those that are, few are generating much in the way of sales, according to survey results released today by email marketing vendor Campaigner.

The survey finds that only 16.6% of the 562 Campaigner clients that took part in the survey offer Buy buttons on at least one social network. And 71.8% of those that are using Buy buttons aren’t generating meaningful sales from them. Another 17.5% said they are generating 1-5% of their revenue from Buy buttons. Those lackluster results, which mirror similar results reported by Macy’s Inc., help explain why 39.7% of respondents said they planned to decrease their use of Buy buttons next year.

While Buy buttons haven’t gained much traction, social media marketing is second, behind only email marketing, in respondents’ rankings of the tools they plan to use more of next year. 73.1% of respondents said they plan to increase their use of email marketing, while 59.8% said social media marketing, 46.3% email newsletters, 45.5% content marketing, 37.6% personalization, 33.8% search engine optimization and 33.1% digital advertising. (Respondents could select more than option).

Those results aren’t surprising given that 38.7% of online retailers in Internet Retailer’s second annual Digital Marketing Survey said email offered the best return on their investment among 10 marketing channels, making it the clear leader over the next most-cited channel, social media, which 16.1% of respondents named.

Moreover, email marketing is cheap. The average cost per order from an email is $5, which is significantly less than behavioral targeting through online ads ($32), remarketing ($26), mobile tactics such as messaging ($25), paid search ($24) and paid social media marketing ($16), according to Forrester Research Inc.’s report “The State of Retailing Online 2016: Marketing and Merchandising.”

Campaigner commissioned the survey, which was conducted Nov. 6-15.