Apparently Microsoft is one of them. Actually our Intranet is pretty good and search on it is very good. Here's the top 10

• American Electric Power (AEP), United States
• Comcast, United States
• DaimlerChrysler AG, Germany
• The Dow Chemical Company, United States
• Infosys Technologies Limited, India
• JPMorgan Chase & Co., United States
• Microsoft Corporation, United States
• National Geographic Society, United States
• The Royal Society for the Protection of Birds (RSPB), United Kingdom
• Volvo Group, Sweden

Lots more detail from Jakob Nielsen.

Link to Intranet Design Annual 2007: Call for Entries