There may be some hand-wringing about the ROI of social media marketing, but brand posts apparently can be a powerful influence in consumer purchase decisions, finds Market Force in a survey of 12,000 consumers in the US and UK to be released later this week. 78% of the US respondents reported that posts by retail, restaurant, travel, entertainment, and financial services businesses they follow on social media have had a moderate to highly influential effect on their purchase decisions. This was close to the proportion (81%) who said that their friends’ posts influence their decisions. Posts from friends are also a way for 3 in 5 US respondents to gather information or opinions about restaurants and retailers. This finding comes on the heels of a March 2012 report from Sociable Labs, which found that 1 in 4 online shoppers, who shop at least quarterly online and login to their Facebook account at least monthly, have made a purchase based on a social recommendation. Read the rest at Marketing Charts.