I'm aware of a few 404's across the website at the moment, this is mostly due to reorganising content from the old tags (getting started, diving deeper, resources, etc) to a new suite of tags that better align with Android Enterprise terminology.
Until I'm finished, you'll see some tags (like fully managed) show blank/404.
I'm working on it.
In the interim, if you're looking for something that isn't where it used to be (I'll fix redirects, too) then jump over to full-text search and you'll find it quick as a flash.
These are short-form posts for small updates and quick thoughts. They are automatically published to social channels, and have their own RSS feed, too.