wonder what is the scope of tiered backlinks in SEO? there have been a debate on diversification and niche related backlinks. so would these non related tiered backlinks will still bring any worth to any backlink profile to enhance rankings on SERPs?
The idea behind obtaining links from pages that are relevant is that a higher percentage of the PageRank is allocated to that link. Links from less relevant pages are understood to be depreciated.
What diversification debate are you referring to? There is a certain amount of confusion around this because people new to links or SEO tend to compartmentalize the different pieces of the issues instead of stepping back and seeing the bigger picture of which this small piece, diversification, is a part of. The big picture is simply that the search engines are establishing baselines for what statistically counts as a normal backlink profile. Anything outside of that baseline is considered abnormal.
There is some confusion arising from what appears to be sites ranking with low quality links. A client asked me about a new competitor with apparently low quality links and was inquiring into whether they should copy those crap links. I then showed him that his backlink checkers failed. I then showed him the REAL links that are powering the competitor site, thousands of links that are not shown by Majestic and Moz's product. In my opinion, a lot of the speculation about how poor quality links still work is based on bad or incomplete information.