I'll post what I know about this. Steam uses a couple types of CD keys/DRM. One way is what EtherealN saw on Shogun, which is when a dev company dumps a mostly unmodified copy of their game on Steam and gives the user a CD key to activate with the dev companies custom CD key activation system. Another example of this would be A-10C with the Starforce system.
Other times a developer will use components of Steam's DRM system, which is believed to allow dev companies to use several different systems, one of which involves a 'hidden' steam CD key. The user should never see it, it is assigned to your Steam account automatically when you first run the game. It automatically activates and unlocks your game right afterwards. It would seem here that Black Shark on Steam uses this system, and had a preexisting pool of keys that ran out during the sale. I believe that whoever at Eagle Dynamics has access to your companies Steam vendor backend (Or whatever fancy name they've given it) has to add more keys through whatever system was setup when the game was first put on steam. Alternatively bug your Steam account manager (The person you contacted when you decided to have your game listed on steam). I'd provide more info if I had it, but Steam forces all devs to obey a pretty strict NDA.
Also, quite a few people are posting on the Steam forum about this. LINK Some are saying they're going for refunds.
TL;DR, bug your business/administration people please.
Also, as a side note, you guys might want to take a look at your activation email template. A message with 'action required' in it from a Russian domain will set off pretty much every spam filter known to man. XD
EDIT: Full disclosure, I bought the game during the Steam daily sale and am also waiting on a key. Would buy Black Shark 2 also, but I can't use it until I can get BS 1 activated, so...
Also, quote from Steam support page on this topic.
