why is sharing disabled on one of my maps?

We disable sharing links on the map page for maps that you specify visibility : private or visibility : friends.  We also hide the embed code for these maps. While outside people couldn’t see these maps anyway, we wouldn’t want you to inadvertently post links that would just bring people to an error page – you’d have a lot of  explainin’ to do.  So we hide the buttons.

Note that for maps with visibility : friends, even if you have connected your Tripline account to Facebook, for privacy purposes on Tripline, your “friends” are your Tripline friends. So be sure to get your Facebook friends to connect to Tripline. When they do, they’ll be added as your Tripline friend automatically and will then be able to see your maps with visibility : friends.