You can now scratch one more big name off the list of apps not available on Windows Phone. Tumblr has just released its official app for Microsoft's mobile platform (the latest version of it, at least), offering all the key features found in its iOS and Android counterparts with a distinct Windows Phone flavor. That includes the ability to swipe left and right to switch between the dashboard and "explore" options, and the option to add the latest images from your dashboard to your lock screen or live tiles. You can also rest assured that animated GIFs will remain animated while you scroll.
Microsoft Windows Phone 7.5