This feature is helpful when you need a common file shared among projects, like a bitmap, readme, set of common tools and utilities, etc.
To add, right-click on the project in the solution explorer, and select Add – Existing Item. You’ll notice the “Add” button is one of those button-dropdowns. Drop down the Add button and select Add a link.
Now you have a linked item in your project as indicated by the shortcut icon.
The location of the linked file is saved in the project file. The location must be via the file system, either on different drives or UNC. No http or ftp.