How commonly do you think Blizzard makes use of some of the social media 'tricks' that apparently many large companies make use of? The PR industry has especially been growing very fast in this area, where they make twitter or forum accounts (by the dozens) to post positive or negative comments under order of the company that hired them.
Making fake accounts to post on your own twitter page and to ask your own account very specific questions with engineered answers to improve your image and to market or advertise some of your products. This habbit has reared it's head since a few years now and is becoming very popular and common among bigger companies. Blizzard moving some of it's employees, devs and community managers to have active twitter accounts can obviously not be seen as a mere consequence or act of benevolence. It's very likely that they too make use of this practice.
2. Forum trolling / fanboying
According to Forbes, last year at least 200.000 people were paid by some gaming company to troll fan forums of a specific game or to continuously post positive feedback about their own game(s). This is apparently also a rapidly growing market, and with MMO-C being one of the largest WoW forums, it would only make sense that some of these 'professional trolls or paid fans' might also regularly post here, either under indirect contract by Blizzard, or by other companies. (EA apparently is the biggest spender when it comes to hiring professional forum trolls to cause bad publicity on forums of other games).