As a reply to my own comment, amazingly on the last Hypercritical podcast (produced on the same day I made that comment, but I had not had a chance to listen to it yet), John Siracusa discussed this very topic. I finally got to listen to it on the way in to work today. I come to the same conclusions and thoughts on stuff as Siracusa so much it's uncanny.

I was not aware at all that Sparrow was inspired by idea of Letters.app, but I was never a Sparrow user and I'm not a Gmail user.

http://5by5.tv/hypercritical/77 - the podcast itself http://www.cultofmac.com/82172/sparrow-was-born-from-letters... http://arstechnica.com/apple/2010/01/rage-against-the-mail-m...