[quote name='noelrock']So can anyone confirm that The Witcher 2 actually activates on Steam? The above link about requesting a digital key is only for GOG, not Steam.[/QUOTE]
The only keys that activate on Steam are Russian region keys. All other region keys will not activate on Steam. You can try your luck with the link that louiedog gave a few posts up. Some people (like myself) were able to get a RU Steam key from the developer provided you showed a proof of purchase. I got mine back in July (right before the Summer Steam Sale). However, some people were only able to activate their keys on GOG. For some reason, I was able to do both.