Sandcastles and modularity on the web
Sometimes websites need to be replaced not because of their age, or technological changes, or changing tastes, or best practices. Sometimes the system you used to build a site is destroyed or "upgraded" to the point that what you have created... and what you rely on... is no longer tenable.
If we accept that the Internet is a constantly changing whirlwind, what can we do to minimize the fallout?
Keep things as separate as you can.