See: http://support.microsoft.com/?id=833987

Courtesy of MVP Frank Saunders:
At this time, support for the beta version of Microsoft Defender is being
provided through the following Microsoft newsgroups:

- microsoft.private.security.spyware.announcements
- microsoft.private.security.spyware.appcompat
- microsoft.private.security.spyware.general
- microsoft.private.security.spyware.install
- microsoft.private.security.spyware.networking
- microsoft.private.security.spyware.signatures
- microsoft.private.security.spyware.onlinecommunity

These newsgroups can be accessed via NNTP or HTTP.

To access these newsgroups using HTTP, please go to the following location:

http://communities.microsoft.com/newsgroups/default.asp?ICP=spyware&sLCID=us
or
http://www.microsoft.com/athome/security/spyware/software/newsgroups/default.mspx

To access these newsgroups using NNTP, please use the following information
for your NNTP client (such as Microsoft Outlook Express):

- NNTP Server: privatenews.microsoft.com
- Account name: privatenews\spyware
- Password: spyware

NOTE: No password will be required via the HTTP link