When a search engine algorithm changes or strengthen, leading to some sites of certain keywords ranking disappeared, some administrators say their site disappeared. Actually is not the case, the search engine algorithm changes or strengthen, will cause some loss of pages , Or filtering, the punishment of certain pages and not the entire site.

If the site’s pages have all disappeared (in the google search sites directly in the URL be able to tell), may be of the following reasons:
a. your server at a critical time can not fault a normal visit;
B. your site exists robots.txt;
c. As a result of improper practices optimize your site search engine was removed from the index;

If only part of the pages keyword ranking dropped, or many pages of keyword ranking are very poor. This may be:
a. optimize the way you appear on the improper conduct was found by search engines;
b. search engine’s algorithm has undergone major changes;
c. you have done some new search engine to run counter to the principle or in the algorithm is allowed before a change of rules, is now illegal, so your site a certain punishment;

Below are some detailed reasons:

1, starting from basic: your server in the near future whether there had been a normal visit to the phenomenon can not be ?
Server can not lead normal visit is the ranking dropped one of the most common factor, so you do not need to carry out any of your site changes, you only need to manage the server, ensure the normal visit, especially in the crucial moment;

2, whether you use the robot.txt file and, if so, then you have recently had their changes and lead to the creation of a number of grammatical mistakes, thereby preventing search engines index your site ?
Robot.txt code in the wrong place or robot.txt wrong location can not be expected to be a lot of potential error factor, if you wish to record your entire search engine site, you need not put the robot.txt file, the default search engine is the case You will include the entire site.

3, whether you continue to the last of your site to optimize it ? Laws can be caused by internal potential errors include:
a. too much of the optimization of a keyword, such as the modified title, meta and <hx> and other labels.
b. internal link structure, especially the link text of the change, if optimization is out for the purpose of amending the text link and the link structure, it is not a novel filter will be a trap, particularly abuse of keywords, keyword density caused by too much.