Read this and answer the question. If the question is unanswerable, say "unanswerable".

The console was first officially announced at E3 2005, and was released at the end of 2006. It was the first console to use Blu-ray Disc as its primary storage medium. The console was the first PlayStation to integrate social gaming services, included it being the first to introduce Sony's social gaming service, PlayStation Network, and its remote connectivity with PlayStation Portable and PlayStation Vita, being able to remote control the console from the devices. In September 2009, the Slim model of the PlayStation 3 was released, being lighter and thinner than the original version, which notably featured a redesigned logo and marketing design, as well as a minor start-up change in software. A Super Slim variation was then released in late 2012, further refining and redesigning the console. As of March 2016, PlayStation 3 has sold 85 million units worldwide. Its successor, the PlayStation 4, was released later in November 2013.

What was officially announced at E4 2005?
unanswerable