Principle of Minimal Constraint

From Well Designed Urls WiKi

delcnari In the essay entitled The World Wide Web: Past, Present and Future published online by Tim Berners-Lee in August 1996, Tim argued that the "Principle of Minimal Constraint" was a major factor in the web's adoption. This is the relevent excerpt from that essay (emphasis ours):

Independence of specifications
Flexibility was clearly a key point. Every specification needed to ensure interoperability 
placed constraints on the implementation and use of the Web. Therefore, as few things  
shouldbe specified as possible (minimal constraint) and those specifications which had to 
be made should be made independent (modularity and information hiding). The independence of 
specifications would allow parts of the design to be replaced while preserving the basic 
architecture. A test of this ability was to replace them with older specifications, and 
demonstrate the ability to intermix those with the new. Thus, the old FTP protocol could be 
intermixed with the new HTTP protocol in the address space, and conventional text documents 
could be intermixed with new hypertext documents.

It is worth pointing out that this principle of minimal constraint was a major factor in the 
web's adoption.  At any point, people needed to make minor and incremental changes to adopt 
the web, first as a parallel technology to existing systems, and then as the principle one.  
The ability to evolve from the past to the present within the general principles of 
architecture gives some hope that evolution into the future will be equally smooth and 
incremental.