The question I would like to answer today is: 'How valuable is it to build links to your sites deep pages?'
The whole issue could be summed up with 1 one sentence: It is VERY valuable to build links to deep pages on your site. Let’s explore why.
Think of your site as a large dam with many tributaries feeding water into it constantly. The tributaries represent all the links pointing to your home page, whether from internal or external links. Your home page is the dam. It is the largest and most popular place for people to link to your site, and therefore usually holds the most weight in the search engines. For the purposes of this analogy, let's say that when the dam releases some water each month, that water then filters out into the surrounding country, eventually making its way back into the tributaries that feed the dam itself (internal links). It's a big circle. That is how page rank gets distributed on your site. Your home page has a lot of 'link juice' pointing at it. That link juice eventually finds it's way to some of the inner pages on your site, but probably won't get to all the pages on your site unless you've only got just a few pages one level from the home page.
So again, why is it valuable to build links to your inner pages (a part of the system of tributaries pointing to the dam) if the home page (dam) of your site will always be the biggest source of traffic and links? Because with larger tributaries feeding it, the dam (your home page) will grow at a faster rate, which will then release more water (page rank/organic ranking) to the surrounding country on a faster schedule, which will, in turn, feed more water into all the tributaries of the dam, not just the one tributary being built up at the time.
If all that is too confusing, here's a real world example:
I have 10 deep pages on my site each targeting a specific keyword. I build 10 links to each of those pages. Since these pages are created in my site template, they all include links back to the home page of my site. So I just got 10 links to my home page, from inner pages on my site that are each getting links themselves. So the inner pages benefit from the links I'm building externally, and if I link to them from the home page as well, they get the added benefit of the strength of my home page too. This creates one big circle of links to deep pages, which link to the home page, and the home page, in turn, links to these deep pages.
One thing to note is that most of the time, you don't get a choice of getting a deep link vs. a home page link and most sites will only link to your home page anyway. So if you have to choose between building links to your home page, or to your inner/deep pages, link to your deep pages. For tips on how to get more links to your deep pages naturally, read my post about link bait.