There is a major difference between Sharepoint 2007 and it's predecessor(like Sharepoint 2003).
Sharepoint 2003 offers great method of aggregating the data from multiple sites to single location, and administrator has to publish the links to the portal areas. That means manual action is required to publish the links to the poratl areas. If he forgot to publish a link to poratl area, business decision makers could not access the information. It is a disadvantage in Sharepoint 2003.
While in Sharepoint 2007, we have built-in webparts like site aggregator and Content Query Web Part meant that site administrators can specify what content should automatically roll up to main portal sites, eliminating manual updates and resulting in sites with up-to-date information.