I've been wondering, what is the difference between ~/Library (i.e. the home-folder's Library), /Library (contained in the root) and /System/Library (contained in the System folder)? I've been installing a couple of plugins for QuickLook and whatnot and I'm always confused as to which Library to use. They all for example have a folder called -/QuickLook. And installing the plugin works in all of them. I know if I put it into ~/Library it will only be available for me, but what would be the difference in placing them in /Library or /System/Library? Thanks!