An enterprise class structure is used to model the internal business segments of a company correct where the divisions and units divide represents the business segments? In my case I am building pega applications to service external clients and for each client there might be customizations. So in other words I am sort of building a product. Now in this case what would the divisions be? Would they still be the business segments of my company or would the divisions represents each client? Or would each client simply be a separate implementation of a framework off of business segments of my company?
I don't think there's a hard and fast rule here. It may make sense for your org to be your company and the divisions to be each customer. If the applications you are using for your customers are similar enough it may make sense for you to reuse org/divisions and separate them out via things like rulesets, you could implement it that way as well. Or you could go the framework route. Is it likely that they will want to define their own org structures or if you give them a predefined one, will that meet their needs? I think the big thing is to think it through, make a decision and then be consistent since all those approaches could be valid.