Using social media to interact with customers pays off, according to the ENGAGEMENTdb report released today by Seattle-based Wetpaint and the Altimeter group, a San Francisco-based digital marketing consultant. Starbucks, Dell and eBay led the way in consumer interactions across 10 different social media outlets such as Facebook and Twitter, according to the report. On average, companies with the highest social networking scores had 18 percent higher revenue over the last year, while those who interacted least through social media saw their revenue drop 6 percent.