not daft at all -- hermes-isms get a little ingrained around here, but their meanings are certainly not self-evident!
a podium order is really just what your store orders to your specs at the semi-annual podiums (podia?) where the managers meet in paris to place orders for their stores. they are presented with a list of what's available and the orders have to be those particular bags, leather and colors. they can place orders for what their clients have requested based on those lists. so if hermes hasn't been able to get a good supply of a certain leather it won't be available for order at that podium.
orders done outside the podium structure are called speical orders, a store can only make a limited number of them, and they take longer to fill.
for example, i want a petrol blei mini kelly, but they are not offering the mini kelly at this podim so i couldn't order it. but if my SA were to offer me a special order i could place that order -- but it will take time until the right leather is available AND there's a craftsman who feels like making a mini kelly with it.
clear as mud?