From WW's forums:
To address the previous  poster, it's been a White WOlf tradition to throw a bash  on the Saturday night of Gen Con--this year's is just part  of a marketing campaign. I know a lot of speculation has  been thrown out there...but the Gen Con registration site 
has updated (though still 100% vague) info on the  announcement. THe quoted summary for the "seminar" is as  follows: "White Wolf/Vampire: The Masquerade Special  Announcement: White Wolf makes a stunning announcement  that will change Vampire: The Masquerade and the World of  Darkness forever! Free T-Shirts and party invitations to the first 500 attendees!"
So. It is DEFINITELY a World of Darkness deal, and seems to be a Vampire announcement--but they may have simply mentioned the most popular WoD game. Again, most of that info isn't new, but it IS official confirmation of this info. More updates to follow.