Ever since a random email invite, I read Andrew Dubber's blog religiously. It's not so much the specifics of the sites or software he talks about, although some of them are useful, but more the overall philosophy and attitude towards the current landscape of the music industry. It's utterly relevant to anyone in media - accept the reality of the online world and find your way of working within it. He deals with many topics, from why DRM is essentially pointless, to the uses and misuses of MySpace, to highlighting individual online marketing ideas. His "20 Things" e-book is also essential reading for any 21st Century muso.