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I think the most exciting news in the blogpost is that Fractals of the Mist features Level Scaling. It's a level 80 dungeon, but everyone will be scaled up to 80, in the same manner as WvW scaling, so anyone can participate.
Also, the difficulty increase for completing multiple "waves" is saved for each character and the difficulty level for a run will be determined by averaging the difficulty tier achieved by each character in the party. No word on when or whether the difficulty level resets for a given character. I would assume it has to reset, or people would hit a wall and not be able to advance further.
This does mean, however, that you don't need to have a pre-mde party ready to play FotM for a long session in order to push the difficulty limits. Characters in the party can be replaced and it may even be seen as beneficial to rotate in characters who have not progressed in difficulty in order to bring the average difficulty level down for groups that have hit the difficulty wall after extended play. I can see this being great for Guilds organizing ongoing FotM runs.
Want to know more about GW2 and why there is so much buzz? Start here: Guild Wars 2 Mass Info for the Uninitiated