Extensions

OpenOffice.org offers the possibility to develop independent 3rd party extensions. The categories of extensions reach from Basic libraries, packages with Java/JavaScript or Python macros to more sophisticated extensions in form of UNO components implemented in Java, C++ or Python. Even the last category of extensions subdivide in general UNO components providing new implementations for existing functional areas or specialized components like Calc Add-Ins, Add-Ons, DataPilots, Chart Add-Ins or linguistic components (e.g. Spellchecker, Hyphenator or Thesaurus).

The Extensions project provides

Tools and guidelines to develop new functionalities for OpenOffice.org
Repository of existing Extensions : listing and classification
Deployement to end-users

Some addons categories

Calc Add-Ins provide new Calc built in functions which can be directly used over the normal function dialog in the Calc application.
Add-Ons describe components providing some new functionality and normally coming with an UI integration (e.g. new menu entries or complete new menues, new toolbars).
DataPilots provide a new kind of data pilot which can be used directly over the DataPilot dialog in the Calc application.
Chart Add-Ins provide a new chart type
Linguistic components provides new implementations of know interfaces which can be used directly over the normal UI.

In the future it should be possible to deploy a collection of new document templates or a gallery as extensions as well.