I stopped reading at this point:
Live tiles finally give you a greater sense of "glance and go."
Currently restricted to use by native WP7 apps only, Mango is opening the door for third-party apps to put dynamic updates directly on their Start menu tiles. We checked out The Weather Channel app and were able to see the temperature and weather condition; push notifications also worked on other apps we tried out such as Beezz (a Twitter client) and Send to WP7. Much like multitasking, this isn't running at full speed yet, but we hope that most apps in the Marketplace will use this new functionality.
My Weather Channel app has had a 'working' live tile since launch. Also rowi, IM+, LazyTube, Smart Tile, Alphajax, AP Mobile, Arkwords, Weatherbug, Flory, TextMe, Flickr, Flixter, Birdsong, Kik Messenger...