No doubt this is part of their PR strategy. "Look, we use Tumblr just like you. We don't have any fancy blogging platform. In fact, we don't have any fancy tool at all. All we do is boring administrative work."

If this is "legit," then it's one of the weirdest things ever. I can't see why any official statement wouldn't be under a .gov.

It appears the answer to the first question is yes: http://www.odni.gov/index.php/carousel-items/916-the-intelli...

As for the second question, yes, it does seem strange.