Zach Williams dissects the Tumblr iPhone app:
After updating the Tumblr application for iOS (and coming across Peter Vidani’s Dribbble shot), I decided to take a stab at seeing how it worked.
Tumblr has many of the same iOS challenges that Facebook does: rendering a timeline of richly formatted posts, with many different layouts and media types, requiring lots of media downloads, and tons of little features in use by enough people that they need to be available in the iPhone app. Then it needs to to be able to create posts in many different formats. It’s much more complex than, say, a Twitter client, so it’s interesting to see how they approach some of the challenges.