I shall copy Mini.

level 1: Batou (machine_purist) and Carrion (cruelty_begs).
level 2: Masmori (shadow_spread). Scratch can know more about Masamori's involvement with the Shadow Organization (i.e. that he's on the Council of Twelve) than Masa's let on in-game. He can also know some of Masa's family background (that his family are kekkaishi who guard Karasumori and so forth). What would be hidden is more information about Masa's personality and thoughts. (If you want more specifics ask me, I can talk about Masa forever.)
level 3: All the rest of mine, those being Megamind (destinedforwhat), Sayaka (contrapuntally), and Ayako (doesitwithtrees). Their apps are all posted on their journals and should give you good information, and feel free to hit me up for any more details!