The media has recently run stories which decry the fact that the WhiteHouse website will start using Web Cookies to track users. Initially I was against this, but the fact of the matter is, just about every website we visit today embeds cookies on the users web cache.
I just checked and JTF uses cookies to allow us to be logged in, by using a session ID. Most browsers do allow you to restrict cookies on certain sites. But most users do not do this, and thus they accumulate many cookies on their machine. It is also possible that cookies can be used in a court of law in order to demonstrate that a defendant visited certain websites.
It is good practice, just for personal privacy reasons, to clear your cookies from time to time. It is possible for the law enforcement agencies to retrieve cookies which were deleted {just as any file which we 'delete' is not truly deleted}.
I thought about this so that JTF users should be aware of how cookies are used. We don't discuss illegal activity here, so for the most part we have nothing to worry about. Should there come a time when our freedom of expression is infringed, then we should learn more about computer security matters.