In addition to events in which neo-Nazis are physically present, there is Right-wing extremist communication by means of electronic mail. It is not uncommon for neo-Nazis to maintain their own web sites and internet services. The neo-Nazis use electronic links to update developments within the right-wing extremist scene. Mailboxes and listserves are used to transmit propaganda, notify sympathizers of sites where rallies and social gatherings will take place, and review books and articles focusing on neo-Nazi politics and topics of interest such as immigration. Coded messages can be transmitted promoting or coordinating illegal violent activity.