Sure, the clock font doesn't matter.  But the limiting form of the formula ("It's OK to let someone else control X because X doesn't matter") for lots of values of X is a recipe for total disaster.<p>We're watching this play out right now with Letters (<a href="http://arstechnica.com/apple/news/2010/01/rage-against-the-mail-machine-the-genesis-of-letters.ars" rel="nofollow">http://arstechnica.com/apple/news/2010/01/rage-against-the-m...</a>) because apparently Apple Mail.app isn't good enough for power-emailers.<p>Nobody expects Letters to become the new default OSX Mail client.  Rather, it will probably be a successful niche app for power users.<p>An app like Letters would never see the light of day on the iPhone because it "duplicates system functionality."  Mail is good enough, so the logic goes.