Starbucks have deployed Microsoft Office Sharepoint Server 2007 for use by approximately 24,000 users in more than 6,000 stores. Their case study and associated solution brief provide a great deal of information covering their business challenge and the Sharepoint solution.
Here's a quote from the case study:
"The store portal was implemented in 2003, and since then has progressed from a non business-critical tool to the primary means for communications between the corporate office and its stores, replacing previous paper-based correspondence. As a result, the store portal visits per week have risen over 190% from 60,000 visits a week to approximately 175,000 visits per week. Additionally, the need for partners to create and have access to business analysis reports, the latest business news and updates, comprehensive search results and training material, has increased. "