What other programs do you use?
Chat, email, skype, video-palyers, FTP, Google Earth, Widgits, screen-savers that connect to the internet? all of these can leave an internet trail. I don't know what you do but just by using a mac your very much safer than an using Xp, Me, 2ooo or VistA. It depends on what your doing and what your worried someone will find.