Since the release of version 4, the development based on version 4 began.
Action Plugin
An Open Contacts action plugin works upon the data of current dynamic data field, providing the Action button with extra menu items. Each of such menu items may trigger a program which take the field data as parameter.
Each plug-in for a custom field is contained in a folder, and all plug-ins are stored under a parent folder called "ActionPlugin". Each plug-in may contain one or many programs that take one parameter for execution. Folder "ActionPlugin" is located under the program folder
This feature was implemented in version 4.1.
Plugin
While writing a standalone program of interacting with Open Contacts is good, in some use cases it is more desirable to have the program running in process with Open Contacts. For example, for additional functions of importing and exporting, it may be good to add buttons to Open Contacts and the users may press the buttons to call related functions.
The buttons will appeared in a floating command bar accommodating commands handled by these programs.
The structure for such features is plugin. The implementation of the structure will be similar to the Action Plugin.
Data exchange with Microsoft Live Contacts, as plugin or standalone program
Yahoo Map services
Distributed Social Networking