The Windows system has several "virtual folders" that aren't folders in the normal sense. They behave in strange ways, making it difficult to pin them, to create shortcuts to them, and even to find them. Mostly, the system consists of a "tree" with branches, a tree of folders within folders within folders, which you see in the Navigation Pane at the left side of every File Explorer window. (If you don't have it fully enabled, select "View > Navigation Pane" and check all the boxes.) But a virtual folder is off by itself, "outside" the tree; there's no "path" to it, because it isn't "in" any other folder. A virtual folder isn't a group of items that really ARE all in one place; instead, it's just a collection of items brought together on the screen, in a display generated by File Explorer, which is made to look like a folder. So here's the scoop on these virtual folders -- what they contain, how to access them, and how to manipulate them. First, their names, descriptions, and contents:

1. Your Libraries (Documents, Pictures, Music, Videos, etc): Most of this stuff is made accessible in the form of regular folders, which are in your User folder. The actual "Libraries" themselves (the ones in the "Libraries" folder) are really a special kind of files rather than folders, but are capable of being displayed in a folder–like format by Windows Explorer. I suspect that all of the "virtual folders" are really special files of some kind; but it may not be possible to access them as files, and at any rate you would have to know their filenames, extensions and paths. When you access them as libraries, using File Explorer, it makes them behave like folders. But that can be done only with those that are called "Libraries".
2. The "Libraries" Folder: Where File Explorer opens by default in Windows 8. This, and the libraries in it, are all virtual folders.
3. The File Explorer "Favorites" Folder: You have your own Favorites folder (in your User Folder) where apps like Bing and Internet Explorer can keep their "Favorites" items. But File Explorer also keeps a few things in its own virtual folder called "Favorites".
4. The Recycle Bin: All links to the Recycle Bin are really shortcuts, even if they don't look like shortcuts. It's a virtual folder, so it isn't really "in" anything.
5. The "Programs" Folder: This is just a visual display in folder form, showing everything in the two "Start Menu" folders (your User SM and the All–Users SM). If a desktop program is in either of those folders, you may be able to launch it from the "Programs Folder." But the many subfolders of the Start Menus, though visible in it, are in some cases not clickable. I'm not sure what purpose this virtual folder was meant to serve; its usefulness to the user is rather limited, and I doubt if the Windows system uses it for any purpose of its own.
6. The "Programs Folder and Fast Items": This is similar to the "Programs Folder" but with a few extra items added.
7. The "Applications" Folder: This is another strange one. It contains almost all apps (Desktop and Metro), and they can be launched from it; but they're all together in one folder (about 150 of them) and not organized into any subfolders, so it's not easy to find something quickly. And some apps, such as the Administrative Tools, seem to be missing.
8. The "Treetop" Folder: I call it that because it's the top of the main "tree" of folders as shown in the Navigation Pane. It's called "Desktop," but that name is confusing since it isn't the same as the real Desktop folder. The real one (i.e. the one that's not "virtual" but an actual folder) has only the same contents as your Desktop and is located in your User folder. The virtual "Treetop" folder also contains some "extras" such as Control Panel, Network, your User folder, the Libraries folder, and the Computer folder. Those "extras" are not regular shortcuts, but a special kind of "virtual" links making those items behave as if they were "in" the Treetop folder. So, like the Recycle Bin icon, they're shortcuts that don't act like shortcuts. When you want to get an ordinary shortcut icon for any item (so you can put the shortcut in a folder and/or create a shortcut key) -- DO NOT copy it from the Treetop folder. Any ordinary item in the Treetop folder will already be on your Desktop and you can copy it from there. If an item is in the Treetop Folder but not on your Desktop, like the "extras" just mentioned, right–click it and select "Create Shortcut". Then find the shortcut created, with an "arrow" icon, and cut–and–paste that to wherever you want it.

Following are some IAQ's (infrequently asked questions) about each of the Virtual Folders.

Q: Can you create a shortcut directly from it?
A: For all of them except the Treetop folder, you can create one very easily. With the folder open, just grab the tiny icon at the left end of the Address Bar (i.e. just before the folder's name) and drag it, using the left button, to the Desktop or into any other folder. That won't move or copy the virtual folder (which can't be done) but will create a shortcut to it. (Warning: DO NOT drag any icons from the Navigation Pane at the left edge of the window. If you do that, you may move a folder without meaning to.) For a direct shortcut to the Treetop Folder, see "Other Tips" below.

Q: Can you pin it to the Start Screen?
A: Yes, after you've created a shortcut. Or, if the folder you want is in the Navigation Pane (see below), you can right–click it there and pin to Start.

Q: Can you pin it to the Taskbar?
A: Yes, but only by creating a shortcut from a CLSID or from a Shell Command (see below).

Q: Does it have a CLSID that you can use to create a shortcut?
A: Most of them do. For the Libraries folder, for example, use the New Shortcut Wizard and type
"explorer shell:::{031E4825–7B94–4DC3–B131–E946B44C8DD5}"
(without the quotes) in the Location pane.
For the others, do the same using the following CLSID's:
Favorites Folder {323CA680–C24D–4099–B94D–446DD2D7249E}
Recycle Bin {645FF040–5081–101B–9F08–00AA002F954E}
Programs Folder {7BE9D83C–A729–4D97–B5A7–1B7313C39E0A}
Programs Folder and Fast Items {865E5E76–AD83–4DCA–A109–50DC2113CE9A}
Applications Folder {4234D49B–0245–4DF3–B780–3893943456E1}

Q: Does it have a Shell Command that you can use to create a shortcut?
A: Only these do. Use the New Shortcut Wizard and type in the Location pane:
For the Libraries Folder -- explorer shell:Libraries
For the Treetop Folder -- explorer shell:Desktop
For the Recycle Bin -- explorer shell:RecycleBinFolder
For the Applications Folder -- explorer shell:AppsFolder

Q: Can you access it by typing its name in the Address Bar of a File Explorer window?
A: Only these.
To access the Programs Folder, type: Programs Folder
For the Applications Folder, type: Applications
For the Libraries Folder, type: Libraries
For the Recycle Bin, type: Recycle Bin
For the Treetop Folder, type: Desktop

Q: Can you pin it to File Explorer's Jump List?
A: Yes, you can do that with all of them. With the folder open, right–click its Taskbar button, hover on the folder's name in the Jump List, and click the tiny "pin" symbol that appears.

Q: Is it shown in the Navigation Pane?
A: At the top of the Pane you'll find Favorites, then Desktop (which is the Treetop folder), then the Libraries folder, and then each Library. At the bottom of the Pane is the Recycle Bin. The other virtual folders aren't shown.

Q: Can you create a Keyboard Shortcut for it?
A: Yes, for all of them. Just create a shortcut icon by any of the above methods, and then you can open its Properties box to create a Keyboard Shortcut. However, Keyboard Shortcuts may not work if the shortcut icon they're created from is in one of your personal folders such as My Documents. So if you're going to want a keyboard Shortcut for a virtual folder, put your shortcut icon for it on the Desktop and then create the Keyboard shortcut from there. Or, if you're going to do this with several folders and you want to save Desktop space, create a new folder on the Desktop and put the shortcut icons in it. But what's on the Desktop has to be the folder itself -- not just a shortcut to it.

Q: Can you get its contents displayed as a cascading Toolbar opening vertically from the Taskbar?
A: For some of them you can. The regular method of creating a toolbar won't work for virtual folders, since they don't appear IN any drive or folder. But I've found that it can also be done from the Navigation Pane. Right–click the Taskbar and select "Toolbars > New Toolbar." In the special folder–like dialog box that opens, you can just click on any folder in the Navigation Pane and then click the "Select Folder" button. So that makes it possible to create a Toolbar for any Library -- or even one for the Libraries folder itself, which will cascade to the individual libraries. That works for the Favorites folder too. However, I can't find any way to make toolbars for the or for the virtual Programs and Applications folders. For the Treetop folder, if you just right–click the Taskbar and select "Toolbars" you'll see "Desktop" in the list of built–in toolbars that are available. Selecting "Desktop" actually makes a Toolbar for the virtual Treetop Folder -- the one that has all the contents of the Desktop plus the "extras" as mentioned above. It cascades to the Control Panel, Network, your User folder, the Libraries folder, and the Computer folder, as well as the Recycle Bin.

Other tips:
Whenever you've just created a shortcut to a virtual folder, decide if you want to change the shortcut's name, or its icon, to make it more recognizable for you. Any such changes should be made immediately — BEFORE you make use of the shortcut in any of the above ways.

If you open the File Explorer Favorites folder (the one at the very top of the navigation Pane) you'll note that it contains an item that I think is one of the most confusing and misleading things in the system. It's called "Desktop Shortcut"; it looks the same as the "Show Desktop" icon; and if you look at its Properties Box, the "Target" address shown is that of your User Desktop folder — but that's not what it links to. Instead, it's really a direct shortcut to the Treetop folder. You can put it on your Desktop to be used as a link to the Treetop folder if you like. But change its name and its icon, because they're both confusing. On my system I assigned it the "tree" icon which is in "C:\Windows\System32\Shell32.dll" and I named it "Treetop." After you've made those changes you can pin it to the Start Screen and/or assign it a Keyboard Shortcut. However, it cannot be pinned to the Taskbar. If you want a Taskbar–pinnable shortcut to the Treetop folder, forget about this one and instead create one using the Shell Command as mentioned above. You can still give it the Treetop name and icon.