[Edit added Apr 28, 2016: Unless of course they are, as noted here.]
More on the phishing front. This arrived in my spam folder with the incongruous subject line:
Gift-Boost a character to Level 90 when you pre-purchase Warlords of Draenor!
That sounds like an announcement asking you to buy the expansion, but the graphic inside purports to have a code for a free copy of the expansion.
This looks to be built on the same template as the Reaper of Souls phishing attempt I mentioned back in January. The game key is likely just as valid, which is to say not valid at all.
Of course, the most egregious part of the whole thing is the statement that the expansion will go live at noon on December 20, 2014. I am not sure some of us can wait that long.