Ever since going native on iOS, the Tumblr app's been on the receiving end of many, many new features and improvements. Now, continuing its ongoing efforts to make the application as good as can be, the microblogging site has released a new version for iPhone, iPod touch and iPad owners. As of today, Tumblr for iOS will now allow posts to be shared via email and a few major social networks -- including, as you'd expect, Facebook and Twitter. In addition, v3.3.1 brings added integration with Pocket and Instapaper, giving users the ability to save content to either service for offline reading at a later time. Busy couple of days, eh, Tumblr?