Merge replication is used when multidirectional replication is needed.
Merge replication has many applications.
Its ability to allow subscribers to modify data increases its usefulness.
Uses of merge replication include the following:
* Interoffice data sharing
Departments handling payroll, accounts payable, and accounts receivable,
for example, can have access to the same data.
Users in each department can modify the data and have the changes merged on the other departments' systems.
* Multisite data sharing
Merge replication can be used when users at multiple locations require the same data
and need to make changes to that data.
* Message passing
Merge replication can be used as a message-passing system,
in which data can be modified and the changes sent back to the originating system.
Source: Microsoft SQL Server 2000 Administrator's Companion Book