1, " nofollow" written in the meta tags on the page, used to tell the search engines don't grab all external and internal links page.
2. index, nofollow: allows to grab this page, but prohibit the following links.
is love Shanghai, Google, Yahoo, MSN in order to deal with spam links (Spam) introduced an attribute, this attribute should be widely used at present.
nofollow tags are typically used in one of two ways:!
2, " nofollow" on the hyperlink, tell the search engines don't grab specific links.
nofollow and other written:
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index (index) and is allowed to follow a link (follow, can also be understood as whether to allow along hyperlinks in web pages to crawl).
nofollow tag using
4. Noindex, nofllow: banned grab this page, this page also banned tracking links.
these spam links caused a certain degree of trouble to the search engine to evaluate the quality of web page, it can be said that nofollow is a very good "link spam firewall".Shanghai Longfeng topics recommended:
3. Noindex, follow: banned grab this page, but allow the following links.
1. index, follow: allows the grasping this page allows tracking links.
has 4 parameters optional, consisting of 4 combinations:
special chain optimization:
Meta robots label must put in the format and between:The
we all know, the reverse link is the chain is an important factor to the search engine ranking web site. In order to add the reverse link, Shanghai dragon cheats in forum and blog content released a large number of irrelevant links with.optimization techniques and methods in the chain can improve the weights of the website deploymentOn the construction of the chain: high quality
Nofollow tag has two functions, one is not simply to link into the weight, reduce the weight of this link, the two part is to make the addition of nofollow does not participate in the website ranking, website weight is easy.
value in content decided to allow the crawl type, must contain two values: