Despite this, retailers are clearly investing resources in establishing a presence on various social media. L2 Think Tank found that the adoption by retailers of Facebook, Twitter, YouTube, Pinterest and Instagram had climbed between 2012 and 2013. Twitter, Facebook and YouTube saw almost complete adoption rates, while the use of Pinterest and Instagram was at 90%. Participation on foursquare, meanwhile, dropped to 10% from 28% last year. Read the rest at eMarketer.