sn's

sn's are so easy to get on to if you know the person's password. for example, i think someone is logging on to emily's sn and i am guessing its nathan or allen. but idk, so i cant really do anything, and emily is on vacation so she cant do anything, and the person won't talk to me so i dont know who it is. it is kinda freaky. i wish they would just go away. what do they get from being on emily's sn if they dont talk to people?