For example, Joe is working on the toolkit.exe executable. Joe has a working version of toolkit.exe and is changing it. In the office next door, Mary is changing the guilib.lib library. Although the toolkit.exe executable is linking with the guilib.lib library, Joe is not changing guilib.lib and does not need a working version of it.
Joe can use the version of guilib.lib built by the build manager. After the integration testing project is built and passes testing, the build manager creates a baseline. The baseline checks in copies of the prep products to make them available to developers. When Joe is ready to get Mary's latest changes to guilib.lib, Joe updates the development project to bring in the latest tested product file.
Why is this something your site might want to use?
This process cuts the amount of extra work developers complete because they do not build products that they do not modify.
You can share products by packaging them into external projects (About external projects) that can be shared.