Mini USA, the American branch of BMW’s Mini Cooper line, tracks everything being said about its brand everywhere on line — in blogs, discussion groups, forums, MySpace pages and much more — then uses what it learns to guide advertising campaigns. At Hewlett-Packard, 50 executives log into their individual blogs each morning to join the ongoing online conversation about each of their product lines, immediately responding to customer problems and concerns. Ernst & Young recruits many of the 3,500 college graduates it hires every year using a career group on Facebook, where it not only posts job information but also answers individual questions from prospective employees. And Del Monte Pet Foods uses a private online community to regularly “chat” with 400 pet lovers whose opinions help shape new products. These are all examples of companies savvy enough to participate in the “groundswell,” according to Charlene Li, vice president and principal analyst at Forrester Research.…