If you're not familiar with the term it means to make something safe/secure by using a trick to hide the vulnerability rather than fixing it, or perhaps when "fixing" it is just isn't possible. Over the years I've seen the value of running SQL on a non-standard port, threats drop to just about zero. On the other hand, I've never wanted to go to the extreme of renaming the administrator account or giving my service accounts names that look like "real" people.
This months TechNet Magazine has a great article The Great Debate: Security by Obscurity and I encourage you to read it, they present both points of view well and while no final all encompassing right answer, this will make sure you understand the value - or lack of - in the various ways we might use obscurity. Hoping I can get my friend Brian Kelley to post some notes, as he is the most security minded guy I know in the SQL space.