What are Google Apps referrals?

What are Google Apps referrals?
Google Apps lets business, schools and organizations offer customized email, instant messaging, document collaboration and calendar services to all of their users, so they can share ideas and work more effectively. These services are all unified by the start page, a unique, dynamic place where users can preview their inboxes and calendars, browse content and links chosen by the organization, and search the web. Organizations can also design and publish web pages with Google Apps. Best of all, everything is hosted by Google, so there's no hardware or software to download, install or maintain. You can visit the Google Apps website for more information.