The new iPhone app Pin Drop lets users to mark location that matter to them. One or two other startups are trying out this, most notable everplaces, still in private beta version. Users can drop their own pins or they can take inspiration from the curated list feature. Each pin can then be assigned to multiple categories allows users to build up a library of their favourite locations. All of a users pin are private unless they choose to share them public. If many become public, thus populate the globe. Users can optionally backup, manage, and view their pins. They will also allow you to use apps built with the Pin Drop API.