One thing Apple fans find maddening about the company we follow so obsessively is its propensity to keep its plans as secret as possible for as long as possible, rather like a poker player who holds his cards close to his chest and carefully reveals nothing when glancing at them.
If there were a card game based on Apple's habitual behavior, it would be one in which the cards lying face-up on the table decide the winner (or at least the provisional winner, since the game goes on indefinitely), but each player can lay down (or pick back up) at most one card per turn, and strategies can change from one round to the next based on what cards others play, as well as what one picks from the deck.
Apple just played its MacBook Air card, and now we wait while the other players respond or pass for Apple's next turn, when we expect to see updated MacBook Pros (which might possibly still include a new 12-inch model). But it's really Apple's subequent turns that have got everybody fidgeting with anticipation.
You may recall that Apple picked back up its PDA (Newton) card, many turns back, but has never discarded it. Everyone knows Apple has a PDA card in its hand, and now, since playing the iPhone card last summer, and iPod touch card shortly after, many are expecting Apple to follow up with that PDA card, dramatically transformed since the last time it was played.
And then there's the unknown cards in Apple's hand, other devices and applications which haven't yet appeared as specific rumors. We know they're there, but we can only guess at what they might be.
It's maddening, and it keeps us on the edges of our seats, waiting for their next turn to come around.