
etiquette-based soCioteCHniCal desiGn 343
13.1.8 Implementation
To deploy a new system over an existing one it must be backwards
compatible; to grow and develop, it must also be useful.
13.1.8.1 Compatibility For a useful new system to catch on it must
rst survive an introductory period when only a few people in the
community actually use it. To survive this phase, it must be backward
compatible with existing, more broadly used systems. Channel e-mail
has two such cases:
1. Non-channel sender: Channel e-mail can treat e-mails from
new senders as channel requests, and reply to accepted senders
with a channel permission: “Press Reply to ...