I know my Trip Advisor map mashes up well on Facebook though the use of a tab on my profile page. This is a fine example of how data can be shared with friends. As a case in point, I can click New York City and ask for help and recommendations from my friends. I, then, see the names and faces of only those who've been there and authorized themselves as capable and willing of providing advice. In fact, they include these folks: Anas, Chip, David, Heather, Lynne, Mark, Michael, Noura, Randa, Sandy, Susan, Terry, Wanda, and Wendy. I'm not likely to need their help at this time, but this does show the power and utility of allowing fairly open privacy settings on Facebook. If one is too private, there is little benefit of being a member at all.
Speaking of sharing, I do wonder if I can put in my Trip Advisor map here. I was entering cities on my
going to list. Spain, Portugal, and Morocco are on the itinerary for four weeks in September and October.