Outside the number of chain
 

The outer chain number refers to exclude those garbage outside chain after being approved by the search engine effective connection. What is the garbage outside chain, in short, the garbage is the chain is seo optimization to the site itself, no good links, to give an example, you want to talk to you waste have contact? Search engine approved the chain is what search engines to grab the chain, the effective connection refers to our seo optimization website is a function of the connection.