As we have implemented solutions over many years customers have asked for specific functionality that was not available in the core products. Also, we have developed tools to accelerate implementations and improve customer ROI.
These developments have been packaged in such as way that they can be reused in a more cost effective way than developing time and again for each customer. Not reinventing the wheel on a per customer basis.
Effectively, we now have a library of products that we use during deployments or on existing client systems that work out more cost effective than the man days required to develop them from scratch.