The Out-of-the-Box (OOTB) IT Portal Site contains two OOTB IT Portal Home Dashboards:
The difference lies in the level of data available to each Dashboard. The logged in OOTB IT Portal Dashboard allows access to the Service Catalog, Document Repositories, department and personal metrics (seen in Widgets), and more.
The anonymous, not-logged-in OOTB Home Dashboard is limited currently to displaying organization information, a community discussion board, and the option to Reset a Password.
Both Dashboards can be configured to display anything in CSM Administrator; these are merely the OOTB IT Portal Home Dashboards. See Building/Managing a Portal for information on how to customize the Portal Site.