A always issue with SharePoint is that administrator have little  or no idea how it is being used. SharePoint does however provide several tools for monitoring  usage and capturing and reporting  errors.  Both WSS and MOSS provide comprehensive site usage  reports which are available at all the levels of the server farm from the SSP to each individual SharePoint site.

Before admins can review site usage reports, site usage reporting must be enabled  for the server farm. Usage reporting occurs in two separate steps:

1.Web servers log site activity to the usage analysis logs.
2.SharePoint analyses the usage by reading  logs from all  servers in the farm and  saves the data to a content database.
SharePoint usage analysis processing is a scheduled job which runs  every 24 hours and as s a result, it is not possible to have  live usage reports.

Note that you do not have to use the usage reporting that ships with  SharePoint, several third-party tools exist to analyze SharePoint’s usage analysis  logs.

The below steps will enable site usage reporting on WSS:

1.Navigate to the Operations page on the Central Administration site.
2.Click   Usage Analysis Processing in the Logging and Reporting section and the Usage Analysis Processing screen will then  appear.
3.Select   Enable Logging .
4.Input the number of log files to create, note that SharePoint can a maximum of 30 days of log files.
5.Select  Enable Usage Analysis Processing .
6.Enter the time of day  to run the usage processing, it is not possible to control the exact time processing starts – the job is simply  submitted during the specified time frame.
7.Click OK.
For SSP  minimal usage reporting is enabled by default. Advanced reporting must be manually enabled if you wish to view more detailed information, such as search query results. Follow the below steps to to enable advanced usage reporting:

1.Navigate to the SharePoint Shared Services Administration site.
2.Select Usage Reporting in the Office SharePoint Usage Reporting section and the Configure Advanced Usage Analysis Processing page will appear.
3.Select  Enable Advanced Usage Analysis Processing .
4.Select  Enable Search Query Logging – Query logging is enabled by default.
5.Click OK to complete.

Before you are able to view usage reports for a site collection, you will need to enable the Reports feature in that site collection.

To do this follow the below steps on every site collection that you wish to view the site usage reports on (note that this feature is only available   in MOSS 2007):

1.Navigate to the top-level site in your site collection.
2.Navigate to the Site Settings page.
3.Select Site Actions > Site Settings > Modify All Site Settings in a MOSS publishing site. Select Site Actions > Site Settings in a team site.
4.Select Site Collection Features in the Site Collection Administration section.
5.Click  Activate for the Reporting feature.

Note that it takes 24 hours to process usage data so expect a delay in being able to view usage reports.