Originally Posted by Lucky Day 
Hmm..like many 3rd party sites Steam has amalgamated there's with Facebook these days. Me wonders if they associate the original account and the key. I also wonder if you can take back your info with just an unlike.
I might try a Lucky Day account to get a key. That's what I do for most sites that demand I register.
My crude understanding is that it is much more like an old credit card imprint machine - they take your card to push it onto the duplication paper, you sign and they keep a copy - and give you back your card. If you get my meaning, you take back the 'card', but they already grabbed an imprint with all of the info.