This is one of the questions I get asked, and one of the easiest ways to explain it has been to use a simple use case.

Currently there are two attachment formats in use for web services, both supported by large companies, MIME and DIME. This caused issues for several of our customers as they had customers that supported both. They either had to a) Get everyone to support the same format, b) Support both formats for all the services they built, c) Tell their customers that this is the format we support and hope their customers could support both. Neither of these solutions is either particularly economic or customer friendly.

To solve the problem Grand Central implemented a configuration option that allowed users to specify the format they wanted their attachments delivered in. This code was extensively optimized to ensure that the actual impact on performance was only a few millisecs. The total investment in design, implementation,QA,and installation was about 4 man months. Now every customer can use the feature and is freed from having to worry about what attachment format everyone else is using, and if they change their format they also do not worry.

The engineering behind this is fairly simple and many will cry I could do that. The answer is yes you could do it but why - what is the value to an organization to build this and similar features. If 50 organizations need to build this the cost is 200 man months, at $10,000/man month we are talking about $2,000,000.00. This is a simple example more complex features cause the numbers to increase dramatically.

While not everything should be in the shared infrastructure this simple example clearly shows the value of shared infrastructure in removing direct costs from the enterprise and reducing friction between organizations.