Shoutbox

My mom is a yahoo acount user.  When she pressed the internet explorer, the homepage is www.yahoo.ca.  When the page loaded, where it says the name of the current user using their yahoo account it said, "lieswillgetu". She pressed mail and it showed their inbox and the persons name was Willie.  She closed is because she was scared what had happened.  Has anyone heard of this or knows if it a hack.  Plz get back to me as soon as you can.

*as well, is it possible for someone to hack our internet account and use it for their own use?*