These 2 topics tend to confuse people the most.  Not knowing the difference between when people subscribe via rss (which is done through feedburner) or to their Newsletter.

Essentially, these are 2 different databases and are entirely seperate from each other and would require 2 separate subscription forms.

RSS Email Subscribers:

If someone is subscribed to your blog via rss, they will receive emails every time you do a new blog post.  The covers your entire blog, so no matter what category you put a post in, they will receive this update in their inbox.  In some cases that can be different, but in the majority of all cases, this will cover the entire blog.

Newsletter Subscribers:

This is when readers/clients subscribe to your newsletter client.  This is usually done through companies like Constant Contact, Mail Chimp, or YMLP.  When someone subscribes this way, they will only get a newsletter that you specifically send out to your subscribers.  This has to manually done within your newsletter client.

Well, can people who subscribe via rss also be subscribed to the newsletter?

Yes and No!  No, in they can not just complete 1 form and be subscribed to both.  They would need to specifically enter their emails in 2 separate subscription forms to be subscribed to both.  However, you can access the emails for your subscribers via rss in your feedburner account and manually enter them in your newsletter client.

How do I access the emails from my RSS subscribers?

Login to your feedburner account.
Click on the feed that has all your subscribers.
Go to Publicize.
Select Email Subscriptions.
Select “View Subscriber Details” (at the bottom of the page)
This will then drop down and show you all your subscribers email addresses.

I don’t have email subscribers to my rss feed. How can I get some?

Follow the same steps above, but after you click Email Subscriptions, you will need to hit Activate to turn this feature on.
Then you’ll copy and paste the “Subscription Form Code” into a widget in your blog for readers to begin subscribing.

Have a question on this that I didn’t cover? Leave it in the comments and I’ll come back to add it!