Is the version of the .Net Framework 3.0 users are pointed to - to download and install - those users who do not already have 3.0 installed and they access a page with the CardSpace object tag - ... is that file they are supposed to download and install the same file/version of 3.0 as on this page?:
Windows CardSpace ships as a part of .NET Framework 3.0. If you want to use CardSpace you will need .NET Framework 3.0. A simple way to know if it is installed is to look for the Windows CardSpace control panel applet (under User Accounts).
On Windows Vista the .NET Framework 3.0 is already installed.
On Windows XP and Windows Server 2003 you will need to install it from the link you gave (the bootstrapper). Alternatively, you can download the EXE
x86: http://go.microsoft.com/fwlink/?LinkId=70848
x64: http://go.microsoft.com/fwlink/?LinkId=70849
