Our good friend Ghostcrawler (I can say that now, because we all got to meet him at BlizzCon the other week) has done his best to explain the new Path of the Titans feature coming in the Cataclysm expansion over in this forum thread. We had this same question come up on last week's podcast as well, and we said pretty much the same thing GC does: Path of the Titans is a brand new way for max-level characters to keep improving themselves. Of course, the feature is still being developed, but the goal is a "gated, not grindy" way (as in, you'll earn rewards by doing things, not by doing them over and over again) to experience character progression outside of just reputation grinding, PvP, or raiding.
He clarifies the idea more later in the thread as well. The different paths of the Titans are meant to be class-independent, but GC says that they do want players to debate which path is best for which class, even if they do end up with a "best" solution in the end. Archaeology is meant to be a part of it, so GC agrees that it could be more of a mandatory secondary profession than Cooking or Fishing has been in the past, but they're aware of that danger. And just because the paths may be tied to dailies or instances doesn't mean they'll work the same: the time in which you can progress might be longer than the daily quest limit or shorter than the weekly raid limit. The idea, as above, is to give players who don't necessarily raid or PvP something else to do with character progression at endgame.
Should be interesting to see what they come up with. Personally, this sounds a little bit to me like D&D's prestige classes -- not nearly as powerful or varied, but a way of separating your character out from the rest of those that chose the same class you did. That's just me being hopeful, though -- Blizzard seems to have a lot of development before we see this as a finished product.
World of Warcraft: Cataclysm will destroy Azeroth as we know it. Nothing will be the same. In WoW.com's Guide to Cataclysm you can find out everything you need to know about WoW's third expansion. From Goblins and Worgens to Mastery and Guild changes, it's all there for your cataclysmic enjoyment.