Lorelle has a whole explanation on how to provide more than just post and comment feeds on your blog. She explains how to add category feeds, with or without RSS icons, making them auto-discoverable, and even add customizable keyword search feeds. She also discusses whether it’s preferable to offer full text or excerpt feeds to your readers. Specific feeds can increase the usability and attractiveness of your blog.

Understanding, Using, and Customizing WordPress Blog Feeds>>