Plug-ins are a powerful way for users to dynamically enhance the functionality of an installed application. Is there a high priority feature you want that is low priority for the developers? Perhaps you can write a plug-in.
Many RSS aggregators support the ability to add plug-ins through the IBlogExtension interface. Started by Simon Fell, the IBlogExtension is intended to provide news aggregators an extensibility point so that they can be hooked into 3rd party blogging tools such as w.Bloggar.
RSS Bandit is one such aggregator. I recently added documentation which includes a walkthrough for building a very simple plug-in. Please let me know if it is helpful or if you find any errors by commenting here or in the RSS Bandit IBlogExtension forum.
I'm working on a more advanced plug-in complete with configuration settings and a GUI that I will present later.