Hi Judy,
The user was added by the .Net Framework update.
In order to run programs designed with .NET, you'll need the .NET
framework installed locally. However, you can visit any website that uses
..NET without having the framework installed.
Reasons for need:
When you run an ASP.Net application on a WebServer, not necessarily on your
local machine, that is the account the Web Server uses for
credentials/permissions.
ASP.NET is a programming framework built on the common language runtime that
can be used on a server to build powerful Web applications. ASP.NET offers
several important advantages over previous Web development models: More
information here:
http://docs.aspng.com/quickstart/aspplus/doc/whatisaspx.aspx
The ASP.NET worker process (Aspnet_wp.exe) should run with a different and
less privileged identity than the Windows default System identity. This
allows the process to run as a relatively untrusted user so that hosted Web
applications do not have administrative privileges and cannot compromise the
integrity of the server. More information here:
http://tinyurl.com/aedb
/top10faqs.htm