The most notable news of the night was the revelation of Dumbledore's sexuality. Jo says Dumbledore was gay and in love with Gellert Grindelwald. JK, in response to the audience's reaction, said "If I had known this would have made you so happy, I would have told you years ago."
Not quite as head-turning, but equally significant, Jo announced Neville Longbottom's marriage with Hannah Abbott. Hannah became the new landlady of the Leaky Cauldron.
Other heart-warming (ha!) news was revealed about Petunia Dursley. The night Harry left Privet Drive, Petunia wanted to tell Harry, "I know what you're up against and I hope it turns out okay."
Stay tuned, more to come soon!
EDIT: Click HERE to see MuggleNet's Emerson Spartz discuss the news on At Large with Geraldo Rivera... and subsequently get parodied on Jimmy Kimmel.