Systems: Chat
write (1)
- Displays to all users (except users blocking all writes)
TalkD
- Binary session request; requires active confirmation
Zephyr
- Delivers messagegrams with Kerberos authentication
Internet Relay Chat (IRC)
- Directed acyclic graph of servers using a ‘gossip’ alg.
- Weak confidentiality of forum content (passwords)
- Robots can automatically trigger events (invitations)