Carrying on the promotion of Windows Phone 8, the official blog has went into details about the changes to the Live Tiles and the Lock Screen. These posts go beyond describing the changes and examine the reasons behind the changes and the design team's thinking on many of the altered elements.

First up, the live tiles. Josh Phillips takes up the story:

For the past nine months, I served as the program manager responsible for driving the redesign of its Start screen—a tall order for a part of the phone that customers and critics already liked and found distinctive. I began one of our first meetings by challenging the team with a single question: “How can we make Start even more personal?”

Microsoft's drive to remove as much of the UI furniture as possible is on show here, illustrated by the 'arrow' on the Live Tile screen and what happened when it was initially removed. Simply put, people couldn't find the app list, so a bundle of testing was undertaken to decide where to put it back, without reinstating the empty gutter on the screen.

At the top it added too much visual clutter. At the bottom it’s out of the way but still provides a nice hint to new Windows Phone owners that there’s something important off the screen. After we made that change, none of our testers overlooked the App list.

And now, the tweaked lock screen, and Windows Mobile blogger Michael Stroh talks to Danielle Ellbogen, program manager behind the lock screen: 

Before we showed the calendar in the detailed status area. Now you can change that calendar slot to things like your email, your phone, your messaging—so you can see who the missed call was from, or read the first couple lines of a new text message. It’s the same amount of detail you’d see in the large Start tile. Apps can also register to be on the lock screen. For example, Facebook could show you new comments or if someone posted on your wall. CNN could show you their top story. Skype could show missed calls... We figured we shouldn’t be deciding these things for the user because it’s such prime real estate. Users should decide what’s most important to them.

One thing to point out here is the changes to the media controls, which under Windows Phone 7.5 are an almost constant presence, and while they are still there on the lock screen, they will fade out three seconds after the power button is pressed to reduce the chances of accidental media incidents.

Read on at the Windows Blog.