Microsoft published a case study about our use of SQL Server 2008. It's a pretty good summary of our how much "stuff" we have to manage.
NewsGator makes life easier for individuals and companies by aggregating Really Simple Syndication (RSS) data feeds from across the Web to provide users with customized content delivery, enabling everyone to essentially create their own electronic newspaper. The company, which also provides Software as a Service to more than 50 media outlets including CNN and USA Today, stores some 2.5 billion RSS articles totalling about 4 terabytes on clustered databases running Microsoft® SQL Server® database Software. NewsGator is upgrading its database infrastructure to SQL Server 2008 Enterprise Edition (64-bit) running on the Windows Server® 2008 for 64-Bit Systems operating system to take advantage of a number of new features, including enhanced Database Mirroring for high availability, Backup Compression to reduce storage needs, and Resource Governor for allocating processing resources.