Presumably then GLaDOS will show up busting a rhyme in Super 8 or riddling it with portal-based puzzlers. It’s accessible through ‘Extras’ on the PC main menu.
It’s kind of an interactive movie trailer for Super 8 although you don’t get to actually ‘interact’ with objects within the teaser. If you don’t own the game or don’t intend to buy it then check out the video from Kotaku.
Portal 2 released on PC today.