Hi folks, Until yesterday I haven't had a chance to play with what you call effects. Because I believe this is a misleading terminology I want to propose an alternative:
Scripts ------- Scripts are little programs, written in interpreted language, that supply extended Inkscape functionality. They can work on objects, or even drav new objects on the canvas.
Both Blender and GIMP projects eventually came to a conclusion that it makes no sense to separate scripts form the core functionality in terms of interface. A script should be free to register anywhere in the menus, based on its functionality. Grouping them, creating yet another menu structure, just because they are written in a particular language is not helpful to the user.
Yes, it is pretty much what you call effects now.
Filters ------- Filters are operations on selected objects, on their bitmap renderings even. The result of the filter replaces the original object and cannot be easily changed in future. The resulting image is stored in the file upon save.
Effects ------- Effects are similar to filters, yet they are "dynamically" applied on a bitmap copy of the object at the target resolution. Only effect settings are stored in the file on save, and the effect needs to be recalculated (possibly some caching/preview voodoo needs to be applied to speed up preview).
cheers