If you want to bring your sites along when switching machines, or sync them via some cloud service, you can change the home directory for IIS Express. Home directory is where all the configuration for web sites is stored.
Changing the User Home Directory
IIS 8.0 Express supports changing the user's home directory, which is mapped to the %IIS_USER_HOME% variable in configuration. By default this path is located at %UserProfile%\Documents\IISExpress, but users can change this by setting a CustomUserHome registry property in HKCU\Software\Microsoft\IISExpress, or by specifying the "/userhome" parameter when launching iisexpress.exe.
From ReadMe (link).