And the winner is: Hashtag. It sounds like they actually mean the symbol, not the word, and that they are specifically referring to the use of a hashtag to key up a self-deprecating remark or some other sort of ironic comment at the end of a twitter or other social media posting. So, for example, I could tack on something like this at the end of nearly any of my posts “#demonstrating my typical succinctness and firm grasp on basic linguistic principles.” I’m not arguing that it is “wrong” to pick a symbol as the word of the year, but it does seem to underscore the value of specifying some sort of criteria. #I’m jus sayin’.
[edit: Ahem, I see they did, at least sort of, explain their criteria in an official press release, and they reference a broader use of hashtag and not just the “ironic little comment” one. But I think the “ironic comment” use of hashtag is the one that makes it a “2012 thing”.]
With regard to HD, I wonder if there was a misnegation in there: perhaps they were nominating, as most unnecessary, the use of HD with regard to a product when it is clear from the context that the product can’t NOT be HD. As in, “I’m pleased with the new 55” LED 1080p HD TV that I just bought.” The “HD” could be said to be unnecessary, since 1080p is high definition by definition. Not that I’m a big fan of this type of peevery, but it would at least make some sort of sense for somebody to say that such a usage is unnecessary, while referring to something that not only isn’t, but can’t be, high-definition as HD is something I can’t recall seeing anybody do, and such a usage would be more bizarre than unnecessary.