Yukari told me some stuff about her past. Are you reading this, Yukari? Is it okay if I post about it here? We 2nd-year girls gotta stick together, after all. :P
EDIT:
She said it's okay to say a little. Her dad... he died in an explosion at a lab run by the Kirijo group (I knew I'd heard Mitsuru's name before...), back in '99.