Every Wednesday, Lucasfilm posts some type of trailer related to the original Star Wars trilogy. At first, the rumor was that Disney was counting down to some type of big reveal back in October to mark the date of the Lucasfilm acquisition.
However, as time has passed, it's looking more and more like Lucasfilm just likes posting old Star Wars trilogy trailers to YouTube on Wednesdays. Of course, there is some speculation that all these old trailers could still be a countdown, but the new date being batted around is a countdown to Wednesday, December 18, 2013. Why a countdown to that date? Well, Star Wars Episode VII is set to be released on December 18, 2015.
However, for right now, we're going to have to label it as just a coincidence that December 18 happens to fall on a Wednesday this year, which is Lucasfilm's favorite day of the week to re-release old trailers.
The new trailer that Lucasfilm re-released today is the 1981 Star Wars Theatrical Re-Release Trailer. Lucasfilm notes that "this re-release was historic, as it would mark the first appearance of Episode IV A New Hope in the movie's opening crawl, officially rebranding the film as Star Wars: Episode IV A New Hope."