The company I work for has in total over 20,000 instances of SQL Server. Crazy to think about from a DBA perspective and literally a nightmare when it comes to data quality and integrity. Steve is right, we are rethinking how we manage these instances, moving them to virtual machines and consolidating them as fast as possible. Gone are the days of just dropping a new instance on a server that has extra capacity 'because you can', each new instance must be justified both from a cost and compliance point of view before it can be deployed.