Kev, I was being entirely sarcastic. Of course there's big differences between a 98 and a '15 model. The only place you'll hear otherwise is on this forum (and sometimes even from otherwise sensible people like Marc).
Walt, I am a little disturbed that a man who makes a living from suspension doesn't know the difference between CC and OC forks, but here goes:
The closed (or twin chamber) fork keeps the dampening oil in a separate, sealed chamber to prevent it aerating under hard use.
The CC fork still has an oil bath in the main leg for seal/bush lubrication and bottoming control.
Did I pass? You never gave me my results when you tested me on progressive springs.
Marc, 1980 to 1986 was an unprecedented time for technological improvement: water cooling, disc brakes, power valves, linkage rear ends, safety seats, cartridge forks, 43mm forks, mainstream flat slides, flat slides that work, USD forks. Even the suspension revolution of the mid 70s paled in the depth and breadth of changes.
You'd be an idiot to dismiss the importance of the suspension revolution, but it's the only era that even dreams of matching the first seven years of the 1980s for technological changes...
The period 98-15 matches the vast majority of MX history for technology changes.