file:appdata

About

Application Data (APPDATA) is a hidden folder where application can saved their data for one user.

To share data between several user, the ProgramData folder should be used.

C:\Users\UserName\AppData

 %APPDATA%

The appdata folders contains three subfolders

C:\Users\UserName\AppData
                           \Local
                            \LocalLow
                            \Roaming

where:

local contains data that will stay on the computer (cache, big file..
localLow contains data that may be used even in Protected mode (with more restricted security settings)
roaming is the data that would roam (ie sync from computer to computer) after a user login on the same domain

The appdata equivalent for linux is a hidden home sub-directory with the name of the application

~/.appName

where: