Using the Change Log
Applies to: SharePoint Foundation 2010
Microsoft SharePoint Foundation includes a change log for tracking changes to selected objects in a list, Web site, site collection, or content database. For example, whenever an item is added to a list, updated, renamed, moved, or deleted, that information is recorded in the change log along with the time of the change and a unique identifier for the item, so that it can be retrieved and modified or perhaps recovered from the Recycle Bin.
The SharePoint Foundation object model offers a rich set of APIs for consuming the change log, making it easy to query at regular intervals and determine which objects have changed, when they were changed, and how they were changed. Among other applications, this information can be used to synchronize data.