access lists are another one of Dreamwidth's killer features, and one of the best reasons to post here rather than anywhere else. They're something most people are likely to use.

Mileage varies - they're of absolutely no use to people who post solely for public consumption, and of not much use to people who use security settings (the Not Safe For Work gubbins) to keep posts from showing up in search engines. To the best of my knowledge, they're also an urban myth to anyone whose browser doesn't run javascript.