I was looking at the Steam page for Age of Empires III (hey, I got nostalgic) and to my surprise noticed I was unable to buy the game. Instead, Steam had given this message:

This game is temporarily unavailable to purchase because Steam is out of third-party keys that are required by the game. Once the publisher provides more keys, the game will be available for purchase again.

I didn't really think that buying things off the Steam store meant you were actually still buying a key in the background.

It also seems bizarre that a game from a relatively well known franchise could be 'out of stock'. I thought we were in the digital future where things didn't go out of stock!

Is this just someone at the publisher Microsoft forgetting to tick a box somewhere? Has anyone ever seen anything like this before?

Yes, have seen that with other MS games too. Fable 3 iirc. It stinks. And they had to hunt down a former employee from Lionhead or something like that.

I have never seen it but it makes sense from a business standpoint: everyone wants you to use their storefront. At least Microsoft didn't just refuse to use Steam like EA did.

This has happened a few times in steam history and it is from what I've heard is steam basically bought volume liscensing from Microsoft and have basically run out of the number of keys from being on sale for a while give it a day or two and there should be more if that.

So I bought GTA IV years ago and had this problem after purchase. Glad they've changed that.

Steam did send me a key for GTA IV the next day or so.