Regarding nofollow, both Zac and Teacher Guoping expressed their opinions. They both said a lot. Teacher Zac believed that nofollow would waste PR and weight, and Teacher Guoping believed that nofollow would waste PR.
Their examples are all like this: Suppose you originally had a page with a PR value of 10 points, and there were 10 links in this page. Before nofollow, each link was assigned a PR value of 1 point. If you nofollow 5 of the links, you think that each of the remaining 5 links can be assigned a PR value of 2 points, but in fact, each link can still only be assigned a PR value of 1 point.
Both of them are based on Matt Cutts's English:
"So what happens when you have a page with “ten PageRank points" and ten outgoing links, and five of those links are nofollowed? Let's leave aside the decay factor to focus on the core part of the question. Originally, the five links without nofollow would have flowed two points of PageRank each (in essence, the nofollowed links didn't count toward the denominator when dividing PageRank by the outdegree of the page). More than a year ago, Google changed how the PageRank flows so that the five links without nofollow would flow one point of PageRank each.”
Original text: http://www.mattcutts.com/blog/pagerank-sculpting/
According to Matt Cutts’ original reasoning, every nofollow link wastes a certain proportion of PR. Assume that your blog has 100 links, 10 of which are from your own site, and 90 of which are comments that you nofollowed. That means you have wasted 90% of your PR. Your PR for each page will become than the previous 10%. Then the PR of blogs with more comments should be lower, but in fact this is not the case. Blogs with hundreds of comments (non-spam comments) generally have higher PR than blogs with no comments; on the other hand, There is no mention of weight here at all!!!
If ""nofollow will waste PR and weight", then the only option is to turn off the comment function on all blogs, the only option is to cancel nofollow on all small websites, and cancel nofollow on large websites if it is not based on the number of inclusions. It is also the only option, but it is obviously impossible.
Google engineers are not retarded. Is the introduction of nofollow by Google critical to the infinite reduction of PR and weight of all people’s blogs?
I think Matt Cutts did not fully address this issue. After all, search engines do not want webmasters to always use various techniques to disrupt rankings. My understanding of Matt Cutts’s words is:
Suppose there is a page PR with 10 points:
If 10 links appear from the beginning and 5 of them are nofollowed, then each undofollowed link will get 2 PR points;
If 10 links are dofollowed at the beginning, and after the weight and PR are transferred, you add nofollow to 5 of them, then each dofollowed link will get 1 PR value. After a period of time, the PR value obtained by dofollow slowly rose back to 2 points.
I hope to continue to exchange views on nofollow with Teacher Guoping and Teacher Zac.
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