Confused by the new privacy settings rolling out on Facebook? The Electronic Frontier Foundation (EFF) has a thorough run down of the changes and recommendations for keeping what you post as private as possible. The best way to keep stuff private, of course, is not to share anything you don't want made public. This is also a good time to remind you to donate to the EFF.
Facebook will justify the new push for more sharing with everyone by pointing to the new per-post privacy options — if you don't want to share a particular piece of content with everyone, Facebook will argue, then just set the privacy level for that piece of content to something else. But we think the much safer option is to do the reverse: set your general privacy default to a more restrictive level, like "Only Friends," and then set the per-post privacy to "Everyone" for those particular things that you're sure you want to share with the world.