Some very sad news came across the wire today (April 19): Levon Helm, drummer and vocalist with the classic rock group simply known as the Band, passed away at the age of 71 after a lengthy battle with throat cancer. The influence of the Band and Helm on today's musicians cannot be overstated, from '90s alt-rockers like the Counting Crows and the Black Crowes to the recent crop of rootsy, Americana acts like Iron and Wine, Mumford and Sons and the Avett Brothers. Here's a look at what alternative and indie rockers are saying about Helm on Twitter as they remember one of the true pioneers of rock 'n' roll: