With Windows 8.1 Update 1, Microsoft has introduced a potentially very confusing naming scheme for future updates. In theory, they could have stuck with the "dot" releases and called this Windows 8.2. Or, called it Windows 8.1 Service Pack 2. Both would apply nicely here.
Like with Windows 8.1, Update 1 introduces a few surface-level changes that could invalidate existing documentation, something a service pack tries not to do.

There is still a "start screen", which is useless on a desktop computer, but there have been a few changes:

• The arrow leading to the "all apps" page and the scrollbar no longer disappear
• There is a button for shutdown and search beside the user's login "tile"
• Larger tile sizes are permitted

Microsoft (and their shills) claim this is all new stuff, yet all of this is functionality we HAD prior to Windows 8. How is any of it new?
Sure, it invalidates help files and exisiting documents for Windows 8.1, so I suppose it's "new" in that sense, but it's all just Microsoft reverting mistakes they shouldn't have made in the first place!

Oh yeah, this is new too. Moving your mouse down to the lower portion of the screen brings up the taskbar. More on this later.

Also new is the ability to "pin" Metro/Modern UI/whatever it is this minute apps to the taskbar. Again, more on this later.

The all apps page is still fairly useless, as it still throws every installed application into your face without much in the way of a hierarchy (or even customizability!)