When an ASP.NET System.Web.HttpResponse.End() is called, the current thread is aborted?

when a System.Web.HttpResponse.End() is called a System.Thread.Abort is being fired, which i'm guessing is (or fires) an exception? I've got some logging and this is being listed in the log file...

A first chance

exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll
12/14/2008 01:09:31::
Error in Path :/authenticate
Raw Url :/authenticate
Message :Thread was being aborted.
Source :mscorlib
Stack Trace :   at System.Threading.Thread.AbortInternal()
   at System.Threading.Thread.Abort(Object stateInfo)
   at System.Web.HttpResponse.End()
   at DotNetOpenId.Response.Send()
   at DotNetOpenId.RelyingParty.AuthenticationRequest.RedirectToProvider()
   at MyProject.Services.Authentication.OpenIdAuthenticationService.GetOpenIdPersonaDetails(Uri serviceUri) in C:\Users\Pure Krome\Documents\Visual Studio 2008\Projects\MyProject\Projects\Services\Authentication\OpenIdAuthenticationService.cs:line 108
   at MyProject.Mvc.Controllers.AuthenticationController.Authenticate() in C:\Users\Pure Krome\Documents\Visual Studio 2008\Projects\MyProject\Projects\MVC Application\Controllers\AuthenticationController.cs:line 69
TargetSite :Void AbortInternal()
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in Ackbar.Mvc.DLL
An exception of type 'System.Threading.ThreadAbortException' occurred in Ackbar.Mvc.DLL but was not handled in user code

Is this normal behavior and is it possible to gracefully abort instead of (what looks like) a sudden abrupt abort?

Update

So far it the common census that it's by design. So i'm wondering if it's possible we could take this question and see if we could tweak the code to make it not feel like we're ending the thread prematurely and gracefully exit ... Possible? Code examples?

Yes, this is indeed by design. Microsoft has even documented it. How else would you stop the rest of your program from execution?