My question "what are the most important ubuntu sysadmin tasks/tools" was down voted as "too general".
Is it? Should the site include some more general backgrounders?
I think some general questions are useful, but it is a question of how general. At some point the question gets too vague, and I think the question you asked was just too vague. Some other questions that are still fairly general, but can be answered well are:
These would provide background information, but the questioner in these cases has been specific enough that a good answer can be provided. Your question wasn't. As I said in a comment to your question, I'd be up for specific questions with use cases - for example