Pinning Folders To The Taskbar In Windows 8?
This is what you need to do in order to pin a folder to the Taskbar, and it will work in both Windows 7 and Windows 8:
Create a shortcut to your chosen folder on the Desktop. Right-click or long-press on the empty space on the Desktop, then select New and then Shortcut.
Click or tap Browse and go to the folder you want, select it and click or tap OK.
This will put the full path of the folder into the Location field, in the Create Shortcut wizard.Before you click Next, you will need to insert the word
explorer, followed by a space (the space is important; without it, this procedure will not work) before the folder's path.You'll then be asked to supply a name for this shortcut. Type in whatever you want and click Finish. The folder shortcut will show up on your Desktop.
Now either drag and drop the shortcut to the Taskbar, or right-click on the shortcut and choose "Pin to taskbar" from the menu that pops up.
Note:
Once your folder shortcut is pinned, you can delete it from your Desktop. Doing this won't affect the taskbar or the Start screen folder at all.
Since the folder icon looks like the Windows/File Explorer icon, you'll probably want to change it to something else. You'll need to do this before you pin.
Source: 7Tutorials (includes screenshots)
In windows 8.1, if you already have explorer/a folder pinned to your taskbar (I believe one is pinned by default), you can just drag and drop a folder onto the already pinned icon to add it to the list of sub-pinned folders.