If your website offers a feed and you care about protecting your copyrighted content, one thing you should make sure to do is have some sort of copyright notice within your blog’s feed.
There are a variety of WordPress plugins out there that allow you to create a footer for your WordPress feed, including Feed Footer, which we have previously reviewed here. Some offer rotated feeds, others allow you to use HTML to display whatever you want, but for the average person with a blog this is mostly fluff.
If you just want the ability to basically add a copyright notice or use a small amount of HTML to promote a product/service, then you will want to check out the RSS Footer WordPress plugin. It allows you to easily plugin in a line of code and choose where in your code it should be displayed.