I received an interview invitation early last week, although not for the interview day in Seattle (I did mine via Skype because of other circumstances). I'm unsure if they reached out to everyone at once, or are doing the Skype applicants first. One of the interviewers said that they hoped to have the interviews concluded and a decision made by the end of March.
Good luck to all!
EDIT: Also I should note that my interview wasn't a phone intervew, like was referenced in previous threads, but rather was in place of the interview in Seattle, again due to extenuating circumstances.