See below for Feb 2012 updated data! On March 21, 2011 Twitter celebrated it's 5th birthday: "200 million users and 1 billion tweets per week". But has it hit the mainstream audience and what is the adoption rate in the manufacturing sector? In November 2010 Pew Internet & American Life Project surveyed more than 2,200 US adult web users and asked, “Do you use Twitter?” Their findings:  8% o…