The Season 6 Teaser promo at the D23 Expo was being shown on a cycle with several of the other Comic Con clips. Unfortunately no new scenes and it is just a compilation of the previous seasons.
So no real spoilers, but some of the old cast members (Charlie, Claire and Michael) are shown in quick flashes in the clip. So to be safe posting it here in the spoilers section.
Youtube Link: http://www.youtube.com/watch?v=YmojmhuaBpA
Source: The ODI