An expandable string value is a value that contains a path partly specified using one or more environment variables. Example: %ProgramFiles%\Internet Explorer.
Yeah, that's like if you wanted to put the path to a file named UserInfo.dat in the user's profile directory (Usually named C:\Users\UserName under Vista+), then you would put %USERPROFILE%\UserInfo.dat, so the program would retrieve the file for the current user.
But I have one question. When we read the value, wwhat is the text returned ?
Answer 1 : %USERPROFILE%\UserInfo.dat
Answer 2 : Something like C:\Users\Jessy V\UserInfo.dat