Lots of theories on that....and every time Google updates its search engine...things change.
It used to be very simple....the person with the most "dofollow" backlinks and a decently written and laid out page about a high search topic easily won the "gaming the monster search engine" game.
It isn't that simple any more, but so far as I am currently aware -"dofollow" backlinks still help out.
Now, that said, if you write well about things you are truly enthusiastic about, and then you've also done the "on page search engine optimization" for your hubs...titled everything with keywords, positioned the capsules attractively, and spit out a few simple social network links, then you shouldn't have to backlink any more.....but if you do, it just might help a bit.
Spending time on backlinking isn't nearly as productive as is spending time writing something that is readable and interesting for persons interested in the topic....second to the actual writing...is the on page SEO stuff....Using keywords in capsule titles, captions, not putting too many or unrelated amazon ads - that is what I mean by "simple on page seo."