Never leave yourself signed into your different accounts on the net, on a communal PC that has many users. i.e. Log out of your blogs, emails, facebooks, myspace, etc, all of it!!!
In doing so you can prevent bad things from happening to you.
Take this previous post for example, "Coming out.Living loud.". That post was compliments of Jared Houston, who, being the good friend he is, decided to use my blogger account, that, in my tired state of mind, decided to leave logged in.
Kids, never trust your mates with your various on line log in's, its a recipe for disaster.