Marketing research firm Covario said Atlanta-based Coca-Cola is the biggest draw among big businesses on Facebook. The San Diego company said Wednesday that Coke has 35 million fans on the social media site, a number growing at nearly 3 percent monthly. Coke typically gets seven posts a month that attract more than 235 comments and nearly 1,750 “likes,” Covario said. Covario studied the Facebook strength -- monthly posts, comments, likes -- of the top 100 spending advertisers as reported in Advertising Age magazine. Covario's top five companies on Facebook are Coke, followed by Hyundai, MTV (Viacom), Disney and Bayer.