Days after it introduced its first mobile ads, Tumblr updated its iOS app to version 3.3.1, adding several important new features.
The new version lets users share posts via social networks such as Twitter and Facebook, as well as save content for later using Instapaper and Pocket. Also, users can now email an entire post and close a photo by flinging it up or down.
Other improvements include GIFs that now animate even while you scroll (works only on iPhone 4S or later and iPad 2 or later), and the "Following" list is now alphabetized and searchable.
Tumblr has recently been on an update spree. Besides introducing mobile ads, it launched a Windows Phone app and redesigned its Android app -- all in the span of three weeks.
You can download the new Tumblr app at Apple's App Store.