how to make multiple feeds?

Hello,

I ran a SEO check on my site and it says I have the following feeds:
http://www.domain.com/comments/feed
http://www.domain.com/feed

And then I checked another site, which actually has way less backlinks and not good onpage results, but is ranked much higher at Google…so I thought this is maybe because THIS page has 4 feeds, but how do I create other feeds? The page I saw has the following feeds:
http://www.domain.com/comments/feed
http://www.domain.com/feed
http://www.domain.com/start/feed
http://www.domain.com/feed
(one is twice)

How did they do this?
Can I do this INSIDE wordpress or do I need another external service?