You can read about the background for this upgrade here. From that post:
We’ve moved all of the content over to WordPress, slightly reworked the organization, added site navigation in the sidebar, and given it a fresh new look. Mark Goodacre will continue on as the editor and will continue to update the site.
Mark has moved the old NT Gateway blog to a new location and will continue to blog there. He has a new RSS feed, so you’ll need to subscribe to it to get all of the new content syndicated. The NT Gateway blog is restarting from scratch. It, too, has an RSS feed that you can subscribe to.