I add "[public]" or "[friends]" to the titles of my posts (and will do in the future even if I have not in the past) so that readers might be more likely to notice when a post is friends-only and so should only be talked about on the comments threads for that post. That said some automatic posts (e.g. from Twitter, usually entitled, "My tweets") will not have that label in the title and so will likely be public. So, if a post foes not have a privacy label in the title, please take note of the padlock icon or its absence.
My sticky post is here and is visible at the top of natf when you lead that in a browser.