What do you want to know exactly the link you provided does tell you the use of the account. Is there a specific question you have regarding this account or do you want more information in general?

This account is used by system progs that run on your computer that need access to the network. http://directoryadmin.blogspot.com

Network Service Account The Network Service account is a built-in account that has more access to resources and objects than members of the Users group. Services that run as the Network Service account access network resources by using the credentials of the computer account in the format <domain_name>\<computer_name>$. The actual name of the account is NT AUTHORITY\NETWORK SERVICE. You can use this account in SQL server, IIS etc. E.g. By default, Microsoft Internet Information Services (IIS) 6.0 on Windows Server 2003 runs ASP.NET applications in application pools that use the NT AUTHORITY\Network Service account identity. This account is a least privileged machine account with limited permissions. An application that runs using this account has restricted access to the event log, registry, and file system. The account does have network credentials, which means you can use it to access network resources and remote databases by using Windows authentication. The network resources must be in the same domain as your Web server or in a trusted domain. In some scenarios, using a custom domain service account is a better approach than using the Network Service account. You should use a custom domain service account if: You want to isolate multiple applications on a single server from one another.You need different access controls for each application on local and remote resources. For example, other applications cannot access your application's databases if access is restricted to your application's account.You want to use Windows auditing to track the activity of each application separately.You want to prevent any accidental or deliberate changes to the access controls or permissions associated with the general purpose Network Service account from affecting your application. Sachin Gadhave (MCP, MCTS)

What is NetworkSecurity Account, what is the use of NetworkSecurity Account? I use the following link. http://msdn.microsoft.com/en-us/library/windows/desktop/ms684272(v=vs.85).aspx. But i am not much clear. Can anyone brief me this?- Santron Manibharathi.