Different types of gems have different basic properties, and a gem's cut also determines the effect this gem will have. Jewelcrafters can learn several types of cuts for each kind of gem: the Azure Moonstone, for example, can be cut into a lustrous, stormy, solid, or sparkling Azure Moonstone, and each one of these cuts offers different bonuses when used in a socketable item. Placing cut gems into an item's sockets will add the bonuses of these gems to those of the item, allowing players to customize their equipment to better suit their individual play style or the different roles their class can fulfill.
It's hard enough just to figure out what fire resistant gear to wear while farming for materials to make more fire resistant gear. Now you have to remember which chestpiece with which combination of gems combined with which helm (combined with which combination of gems) combined with... ARGH.
Can it be long before there's an undergraduate class in World of Warcraft gear? If Blizzard let the goods be traded openly, for dough, we'd probably not be that far out. Hrm, speaking of, I'd better log Thopas Columbia back into Second Life to get my 50 Lindens.
Oh dear GOD you're so right on the money with this. I was playing Baldur's Gate 2 with a friend a month ago, which is a MMORPG if two people with PS2 controllers can be considered MMO, and I was so aggressively disinterested in the "deep" arbitrary object enhandement system that sucked in all my friend's interest like GameFAQs were a centerfold.
Notice how the linked-to page has "The Art of Jewelcrafting" in huge, suitable for the cover of a Forgotten Realms novel, letters. How they call their little system of trial-and-error discovery and institutionalized min-maxing an "art." They actually view all this as a good thing.
You know the game that inflicted all this upon us? Yeah, like so much else of what's wrong with RPGs (MMO or otherwise) these days, it was Final Fantasy VII. DEAR GOD, THANK YOU SQUARE FOR INFLICTING MATERIA UPON AN UNSUSPECTING INDUSTRY.
Ahem. Okay maybe that's hyperbole, but even City of Heroes, which barely has an inventory at all, has its own version of this in its Training/DO/SO enhancement combo system. Now I wonder why I let my subscription to that lapse....