Once upon a time, being a “diehard fan” meant buying a band’s album, show ticket, T-shirt, limited edition signed LP — anything your earnings would allow. Today the term can have a very different meaning. You can be a “diehard” by blogging about everything the band puts out, posting links to your Facebook wall, re-Tweeting the band’s messages, and commenting on its Soundcloud page, all without paying a dime.