Exploration might be the absolutely most exciting thing for me and most other "explorer" types under Bartle's system.
The unfortunate downside to this is that, after something is explored, the magic dies with it. There are some other interesting attributes to an explored zone like returning to an old zone as a "coming home" feeling, and being able to navigate better, but they are undoubtedly less powerful conditions than the original "unexplored" state.
Is it possible at all for MMO developers to counter this other than just indefinitely expanding their games by continuously adding new explorable areas?
There are certainly some players that don't care about exploration, so clearly I'm not asking for your opinions here, you don't care about this, but for everyone else who considers zone exploration one of the main draws of a new game or expansion - what do you think are new and interesting ways to solve this problem?