Some staff may not be aware that system administrators are usually able to access everything on the network. It should be regarded as insecure unless it has been encoded or encrypted. E-mail is often compared to a postcard in that anyone who receives it can read it. E-mail may also be read if it is stored on servers during transmission. E-mails are hard to destroy.
Many people think that if they delete their e-mail it is gone forever.
This is not so as most electronic documents are backed up and recoverable. Most software used to operate networks, including web servers, mail servers and gateways, logs transactions and communications. The content of e-mails themselves would not normally be logged but may be stored on mail servers. Similarly, web server logs record information on the sites that people visit. The keeping of these logs is usually necessary for the routine maintenance and management of networks and systems.