Diablo III's Shared Stash Explained

A new blog entry on the official Diablo III website takes us through the intricacies of one of the highly-requested features being added to the action RPG: an account-wide shared stash.  I can't see any multiplayer RPG being released without one these days:
In addition to a character's personal inventory, players in Diablo III will also have access to a shared stash, a new storage option which can be used by all characters on a Diablo III account. Accessible from each major town at the beginning of every act, the shared stash will give you an unprecedented amount of storage space, more flexibility when it comes to inventory management, and -- perhaps most importantly -- the ability to share the items you collect (or create) with whichever of your characters need them most.

While players will start out with only a single tab in their shared stash with a limited number of slots, upgrades in the form of additional slots and tabs can be purchased for gold by any character you create. You'll be able to buy up to 5 tabs, each containing 70 slots of space, for a total of 350 slots of shared storage! Once bought, the upgraded storage space will be available to every character on your Diablo III account.

In addition, gold is now pooled across an entire account, and "normal" characters can even trade certain items to their "hardcore" brethren:
Hardcore characters are a breed apart. With the challenges and rigors of that play style in mind, it's important to note that Hardcore characters on a Diablo III account will share exclusive access to a shared stash (as well as an auction house and gold pool) that's completely separate from the one used by Normal characters. Players will still be able trade items between their Hardcore characters, but they won't be able to give Normal characters access to anything that's only available on Hardcore Mode, or vice versa.