The community of Android "hackers" has once again done it. They managed to create a permanent root for HTC's almost unbreakable hardware lock, that reversed their phones to the original Android version as soon as it was modified.
I don't know if it's T-mobile and other carriers who requested this "feature", or if it was HTC itself who wanted it, but whoever it was will hopefully learn their lesson that people want full control over their phones. If they keep up with it, people will want their phones less and less, especially if it becomes ever harder for the community of developers to break their root locks.
This exploit was found by Scott Walker, and you'll see it soon enough in custom ROM's like the Cyanogen Mod and MIUI. Check out the details at the source link.