Let's share the good news first—if you are using SharePoint Portal Server out-of-the-box, the index will be kept up to date. The Web Storage System, the place where all documents are maintained by SharePoint Portal Server, sends notifications to the index engine.
The same notification mechanism is available for content sources pointing to a file share. The notification mechanism does not work, however, when indexing other workspaces, Web sites, Exchange Public Folders, and Lotus Notes databases. To keep the index accurate, you must fall back to mechanisms that actively crawl for changes.
→ To learn more about incremental updates, see “Building the Index,” p. 99.
The incremental update ensures that all changes in content ...