After updating their iPhone app in order to be compatible with iOS 4, it looks as if Tumblr has added an extra feature that will please tweetaholics.
Reblog posts to any of your blogs using the native editor. Even peek at the original post if you need to. [...]
Click-through links and uploading via URL are now supported. [...] ‘Send to Twitter’ switch now respects your individual blog settings. (Official Tumblr Blog)
While the native reblogging feature was long overdue (as defaulting to the web version in between was annoying), the selective “tweet your post” feature should make it easier to share specific posts to the twitterverse.
The click through link feature is also another welcoming development, as it will make it easier for Tumblrers to credit (via link) artwork discovered online and posted to their blogs.
Tumblr has not hinted on whether they will expand this feature to Facebook as well (instead of the default “share all or none” mode), although it’s good to see the company pack more features into their mobile apps.