Marco Arment is well-known and well-regarded in Apple fanblogger circles. He's both a developer (he was CTO at Tumblr, and then created Instapaper) and a pundit whose articles often contain footnotes, just like David Foster Wallace. The main thing to know about passionate Apple bloggers and podcasters like Marco Arment is that Rule Number 1 is that you never say anything bad about Apple. That's why today the world of Apple lovers has been shaken to the core — because Marco Arment has violated the prime directive, and declared that Apple's software, well, kind of blows: