At the bottom of each post, you'll see buttons to reblog or Like, as well as hyperlinked tags, all of which make it easy to quickly interact with a post or to follow up on specific topics as you scroll through your feed.
The navigation bar at the top of the app is about as simple as it gets, with three navigation tabs. The first tab brings you to your feed and the second tab shows you tags and a search module. Under the third tab, you'll find notifications, and Tumblr profile details, as well as links to settings and a menu for searching through Tumblr blogs by category.
With the latest update to the app, the Create post functions have been built into an unobtrusive round button that sits at the bottom of the screen. This little button, when tapped, rolls out six more buttons for Video, Chat, Link, Quote, Photo, and Text posts.
The post editors, while convenient and simple, are noticeably more bare bones than their counterparts on the Web. For instance the text post editor lacks formatting buttons for making text bold, creating bullet lists, and adding other style elements, and the photo post editor only lets you add one photo while the full Web version lets you add up to ten. Also, there is no button for creating audio posts like there is on the Web. One thing the editors do include, though, is the ability to save drafts and schedule for later publishing, which is convenient.
If you own a Tumblr blog, then frankly, this mobile app is a must. It makes it incredibly easy to post any type of media to your site (except audio), and it provides a nice interface for keeping up with the Tumblr blogs you follow. That said, I still hope to see landscape support and a tablet-optimized version in the future.