A ZyncroApp is a software module that can be developed to add new features and functionality to a Zyncro social network. A ZyncroApp has front-end components like JavaScript, CSS, HTML and back-end components like PHP and MySQL. ZyncroApps come in two types - organization level apps that are available to all users in an organization, and user level apps that individual users can activate. The document provides information on developing ZyncroApps including JavaScript structure, available methods, adding components to the GUI, and customizing the UI.