I read a blog post that I thought offered bad link building advice. The article was about building links to the homepage. I believe it is important to be aware of the number of links that lead to the home page.
No one can know for sure whether there is an optimal ratio between the homepage and deep links. Google does not publish this kind of information. The ideas contained in this article must therefore be circumspect in its conclusions.
Up to 50% links to the homepage, a bad thing?
The blogger suggested that an ideal of 30% to 50% links to the homepage was realistic.
Neither the targets of 30% nor 50% of links to the homepage are justified by observations or studies. These percentages reflect its objectives in response to the difficulty of encouraging natural links to product pages.
The SEO blogger also stated his (unsubstantiated) opinion that it is common for sites to link to the homepages of other sites.
An excess of homepage links has been noted as a statistical quality of sites that create unnatural links. For example, a 2006 study titled “Characterization and Link-Based Detection of Web Spam » the author states that a statistical study of inbound link patterns found that sites with inbound links primarily to the home page tended to be spammy.
According to this research, non-spam sites tend to have more links to inner pages than to the homepage. See section 3 of the study (PDF).
Several years ago I started using the SEO tool to sample a variety of search queries across a range of niches to find their homepage vs deep linking reports and continued to monitor link patterns. There are many tools that offer home page deep linking metrics.
What I discovered was that the inbound link ratio of sites ranked in the top ten SERPs of Google tended to have more deep links than homepage links. But this was not true in all areas.
Here are some exceptions:
1. For queries with a geographic component, higher ranking sites tend to acquire a higher ratio of links to the homepage. This makes sense because the homepage will be the answer to local queries.
2. Business Pages
Some business pages are dry and lack link-worthy content on inner pages.
3. Competitive Topics
It could be that the lack of sites that would link to inner pages in a natural way is rare. For example, what blogger or web editor would enthusiastically link to a payday loan or gambling website?
Deep link to homepage ratios
I found that the top-ranked online retail sites tended to have a higher ratio of deep links to homepage links.
Some sites, like gas station brands, tended to have more links to the homepage. This may reflect a natural bonding pattern.
Will Too Many Homepage Links Affect Your Rankings?
I don’t think Google uses deep link to homepage ratios to determine if a site is spammy. Many Fortune 500 sites have more homepage links than inner page links. Obviously, the homepage’s deep linking signal alone cannot predict the undesirability of a site.
I believe it’s better to publicize the inner pages so they gain links than to link to the homepage and hope that enough PageRank will trickle down to the important product pages. A link is a vote. It tells Google that a page is important.
It therefore makes sense that a natural and relevant link to a product page is preferable to a link to the home page. That’s why I think, in my experience, that encouraging links to the pages you want to rank for is a better strategy than encouraging links to the homepage.