Where do we draw the line on server questions? I personally think that questions about Apache, Postfix, Postgres, OpenLDAP, etc ought to be offtopic and sent to SF. I even think this question should be sent to SF and not here. I know people are going to ask some questions in relation to servers here, but I feel it should have a significant tie in to Unix.
I think the key understanding here is whether or not the question is about software or a concept with a platform-independent purpose.
- Is there a Windows version?
- Is there an alternative that provides similar functionality available for Windows?
- Can you do the same thing on Windows?
For example, Apache and Postgres have Windows versions and mail and LDAP servers are available for Windows.
The question to which you refer, however, fits in a grey area. I agree with you that as posed it should be on SF (and also CW) but I think it is valid with a title change to say:
What guides are available for securing Ubuntu Lucid Server? (as CW) OR
How can I harden Ubuntu Lucid Server to run Y using Z? (not CW)
and refocusing the question to mention the specific applications that will be used, what has been done so far and any specific concerns they have--especially if they are *nix specific (e.g., sockets, remote administration permissions).