Facebook users should be aware that not all facebook information is private, and that there has been hacking in the past to reveal users personal information. Most sources say your individually addressed emails are secure.  (facebook and other emails).

A "secret" group page is reasonably secure.  The name of the group, the members, and all material in the group is hidden from all non-members, whether they are on facebook or not.  Of course, facebook administrators have access to your information.  (But so do your bank administrators.)

Facebook has just changed your default notification settings to restrict your emails from facebook to "important stories" (whatever that means).  You can still adjust individual settings to suit your preferences.

You can (and should) protect your personal information, by restricting access to it.  The main problem with facebook is you can accidentally post stuff on your "wall" that you didn't really want "everyone" to see.  Be careful.  Also, If you use a lot of apps, advertising folks will mine your information and target adds to your preferences.  (This can be controlled -- increase all privacy settings, as described later.)