An eBook by Addy Osmani on everything you could want to know, and then some, about the most efficient ways to serve images in browsers.
Wonderful piece by Mark Pilgrim on the danger of letting someone else control your music through encryption. As he so nicely puts it:
he left hand knows exactly what the right hand is doing: they’re both giving you the finger.
And yes, this does include iTunes. Plus or not, they still con you, although they are admittedly a bit more fair in their approach.