A problem with the Joomla content component is that it provides an easy way for spammers to get hold of your author emails using your articles feed. One way to stop that is to change the site configuration to use the site email instead, but this is not always a good solution, because you may want to use your site email address to do things like actually contact people, and don't want to get a lot of spam at that address.
So we made this little plugin instead, you can just install it and enable it, then in the plugin configuration set the email address you want to use in feeds. If you want to see an example take a look at our site home page in feed version using the demo link, then right-click to view the source, you will see we have replaced our site email address with firstname.lastname@example.org.
You can set the email address to whatever value you want, eg just create a junk email account to use in feeds, use its address, then check it once a month just in case it actually receives a message that is not spam.
The plugin is compatible with Joomla 2.5 and 3, and will work with feeds generated by the Joomla content component.