public discuss
start with newstweek video (need to find the right one, one of the first, not about the newstweek network thing) -- or with 'meningrey' by the same artists (weise7 / j.oliver / critical engineering)
and/or one of the first cartoons in NYT about the internet
not to spread FUD (NSA style, calling in the A-team to mess things up for you), just showing how people trust unknown networks.
 praxis tables
spread some topics over different tables (depending on who's around to give good info) (email/gpg, https/ssl, tor, password managers etc.)
focus on practically using crypto in your daily computer habits, showing how things work behind the curtains, and how to get user back in control
only publicly handout correct,verifiable info https://securityinabox.org/ or the cryptohandbook (don't know the state of this one, or the update dynamics nowadays though...) : make sure people can check/reread things for themselves and know how to find good info...
 more general
only then tackle the more general problems with privacy on the internet. (people won't get of facebook for this, but bit of awareness won't hurt...) --