There are several ways that people might want to use Tahoe.  We're not necessarily committed to satisfying all of these use cases -- these are just possibilities.

Use Cases
||__name__||__number of nodes__||__administrative domains__||__node capacity__||__node availability__||__churn__||
||''friendnet''||2-10||many domains, but all trusted||mixed||mixed||low||
||''proprietary grid''||2-30||one domain||uniform||high||low||
||''hivecache''||10-1000||one domain, but not as well controlled||somewhat uniform||high||low||
||''Allmydata plus customers''||10-10,000||many||mixed||mixed||medium||
||''global grid''||any||many||mixed||mixed||high||

 * ''friendnet'': a group of friends who want to share backup and file-sharing
 * ''proprietary grid'': a sysadmin, or Allmydata Inc. wants to backup data onto a set of servers
 * ''hivecache'': a sysadmin wants to backup data onto hundreds of employee workstations
 * ''Allmydata plus customers'': Allmydata, Inc. and its customers operating a storage grid including the customer's computers
 * ''global grid'': a large, diverse ecosystem of people and organizations who want a storage grid with extremely high reliability and availability