Although the Web is widely used today, for it to be truly effective part of daily work, it must provide both dependable availability and performance.
Replication has the potential to improve both availability and performance in the Web.
An increasingly important special-case for availability is mobile computing. A portable computer is often intentionally disconnected from the network. Although a number of wireless approaches to communications have been proposed, but cost and geography often prevent their use. Data replication on portable computers can again address this availability problem. Performance is the other major motivation for replication.