The Path of the Titans is gone

The whole Path of the Titans idea has been removed from the game. It will no longer rely on Archeology or on any kind of PvE/PvP progression and instead Blizzard will just introduce a new type of glyphs: Medium Glyphs.

Medium Glyphs will add a "fun factor" to abilities, and it wouldn't be surprising to see something similar to the Fortification or Breakthrough glyphs first previewed during Blizzcon 2009. (But probably not these exact glyphs, a lot of stuff happened since last year)
Archaeology is less important with it being gone
With the Path of the Titans gone, Archeology will become a "true" secondary profession and you won't really have to level it anymore. However it will still be used to let you get cosmetic/optional items, get more information on the game's lore, and ultimately it looks like we can expect rewards similar to fishing. (Nothing mandatory, but you'll be happy when you actually find something)

Information gathered from other sites:[list][*]You will find two types of items: Common Artifacts will give you more information on the lore of a race, and might be used in some kind of collection game. Rare items will give you usable items, most of them will be cosmetic but some of them will have actual effects.
Heroic VC/SFK
Heroic versions of classic instances might not be ready for the release of Cataclysm and will be shipped in content patch instead.
Heirlooms
The current heirlooms will stop growing after level 80. There will be a whole new crop of heirlooms for Cataclysm. Goblins and Worgen will be able to start using heirlooms immediately at launch.