Sharing of code is commonly required but not commonly archived.  The main obstacles towards code sharing is that too much knowledge about the environment is contained in every piece of codes, and when such environment changes, the piece of code needs to be rewritten.  As long as there require adaptations, there is no true sharing.

Object-orientedness solves this issue to a certain extent in separating the atomic pieces of codes.  In a web portal environment, we need to separate the business logics (the codes) and the appearance (the artwork), so that each client have their own "skin" and preferences, so that sharing can be archived beyond the code level.  We share applications, generosely:

• HTML pages can be copied to or shared by different web sites without changes.  All client-dependent information including preferences, content, authentication and resource allocation are separated from the code (the CROFT and Scheme to be discussed later).