From FAQ of Area 51:
Off-topic questions are important, too
If you have a good, useful question in mind, but aren't completely sure that it's on topic, ask it anyway; others can then discuss the subject and together determine if it is appropriate for the site. Questions that simply don't fit in the scope of the site should be closed, indicating that, while perhaps interesting, this topic is inappropriate for this site. This helps to define the very outer boundary of a site.
According to the text above, I should ask off-topic. People will down vote that question as that is not useful. This helps to define the site. But that page also says that down voting a question will also cause the author to lose two reputation. This is a confusing.