How to write the Nofollow tag and introduction to the use of nofollow_HTML/Xhtml_Web page production

The "nofollow" tag is a tag proposed by Google, Yahoo and Microsoft a few years ago. After adding this tag to the link, the weight will not be calculated. Search engines support the nofollow attribute, which inhibits blogging to a large extent. Or spam messages on the forum. This is a great thing for webmasters.

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

Use of nofollow

Nofollow has two uses:
1. Used for meta meta tags: , telling the crawler that all links on the page do not need to be followed.
2. Used for a tag: Login, telling the crawler that the page does not need to be tracked.

The role of nofollow

nofollow has three main functions:
1. To prevent untrustworthy content, the most common of which is spam messages and comments on blogs to obtain external links, and to prevent pages from pointing to spam pages and sites. .
2. Paid links: In order to prevent paid links from affecting Google’s search result rankings, Google recommends using the nofollow attribute.
3. Guide crawlers to crawl valid pages: Avoid crawlers from crawling some meaningless pages, which will affect the efficiency of crawlers.

PR pruning (Pagerank Sculpting)

Abuse of nofollow. In order to achieve maximum search engine optimization, some SEOs use nofollow to control the flow of PR, which can optimize some specific pages. Of course, this kind of optimization is more suitable for some old sites that have accumulated a considerable amount of PR. In order to prevent PR pruning and the abuse of nofollow, Google has weakened the role of nofollow. The previous nofollow not only did not cause PR flow, but also did not cause PR loss. Although the current nofollow regulations will not cause PR flow to the target page, it will not cause PR flow to the target page. The original flow to the target page will be lost. For example, the PR of the current page is 1, and there are 10 links on the page, one of which is a nofollow link. According to the previous nofollow regulations, the target page pointed to by each non-nofollow link will get 1/9 of the PR of the link containing nofollow. PR cannot be obtained, and according to Google's new regulations on nofollow, the target page pointed to by the non-nofollow link can only obtain 1/10, and the nofollow link cannot obtain PR, which means that 1/10 of the PR is lost.

SEO Recommendations
The role of nofollow in Google is already very weak, so SEO needs to control the flow of PR on the site to avoid links pointing to spam pages, and can only rely on manual review.

Let’s look at an example first, how to write the nofollow tag, take my blog as an example:

A normal A tag is as follows: