I happened to spy one on the drink cart as it came down the aisle of the Embraer Jet. The flight attendant told me that thee cart is stocked with only one can per flight. On my return flight, another flight attendant said some Embraer jets have TWO whole cans. The way to tell, she said: look for the curved wing tip out the window. That means the plane has a bigger galley and thus room for two drink carts.
So, on your next flight, realize that you have more beverage options, but if you want a Coke Zero, you may have to fight for it, especially now that the secret is out. Continental has advertised that it offers Coke Zero on its napkins (as Lucky shows us on the One Mile at a Time blog) and the caper of the Coke Zero can even has its own topic over at FlyerTalk.