Microsoft debuted shape writing during the keynote, which allows user to type more quickly by swiping from letter to letter, rather than inputting each letter individually. Joe Belfiore said that even though he doesn't like to play favorites, he can't image how he lived before without shape writing.
And when he demoed it during the presentation, he only had one mispelling in the phrase "Being on stage at Build is simultaneously delightful and horrifying. Of course I love to hear from developers, but occasionally techies can be intimidating." The second word, "on" was originally intepreted as "IV."