Shulou(Shulou.com)06/01 Report--

Nofollow is a value of the content attribute of the HTML meta tag (meta) and the rel attribute of the link tag (a), telling the machine (crawler) that there is no need to track the target page, and that to combat blogspam (blog spam), Google recommends using nofollow, telling the search engine crawler that there is no need to crawl the target page, and that the search engine does not need to pass the Pagerank of the current page to the target page. But if you submit the page directly through sitemap, the crawler will still crawl. The nofollow here is only an attitude of the current page to the target page, not the attitude of other pages to the target page.

The use of nofollow

Nofollow can be used in two ways:

1. For meta meta tags: tell the crawler that all links on this page do not need to be tracked.

two。 For a tag: log in and tell the crawler that the page does not need to be tracked.

The role of nofollow

Nofollow has three main functions:

1. To prevent untrusted content, the most common are spam messages on blogs and comments in order to get spam links outside the link, in order to prevent the page from pointing to some pull pages and sites.

two。 Paid links: to prevent paid links from affecting Google's search results rankings, Google recommends using the nofollow attribute.

3. Guide the crawler to grab effective pages: prevent the crawler from grabbing some meaningless pages, which affects the efficiency of crawling.

PR pruning (Pagerank Sculpting)

The abuse of nofollow, some SEO in order to achieve the maximum search engine optimization, through nofollow to control the flow of PR, can be very good to optimize some specific pages. Of course, this optimization is more suitable for some old sites that have accumulated a considerable amount of PR. In order to prevent PR pruning and abuse of nofollow, Google has weakened the role of nofollow, the previous nofollow not only will not cause PR flow, but also will not cause PR loss, although the current nofollow regulations will not cause PR to flow to the target page, but the original flow of the target page will be lost. For example, the current page PR is 1, and there are 10 links on the page, one of which is a nofollow link, according to the previous nofollow, each non-nofollow link to the target page will get a PR of 1 nofollow 9, a link with nofollow can not get PR, and according to the new regulations of Google on nofollow, the target page of non-nofollow links can only get a PR, that is, a loss of 1max 10 PR.

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