The emphasis in your workplace may seem to be on security and privacy, but this is a complex issue. What seems right doesn't always follow. It's important to know where you stand. If a letter is addressed to a person and a company, legally the employer can assume it belongs to the company. This is an area where commonsense should prevail.
Some companies log mail as a matter of efficiency to keep track of what has arrived.
Just to be sure, if you're expecting something personal, notify the mailroom. Email and Web browsing The privacy of workplace email and Web browsing is a hot topic. If you're tempted to send lurid details or true confessions via the office email, forget it. Most email is insecure unless it has been encoded or encrypted. Like a postcard, anyone can read it.