Why my site is not indexed?

As you know, all of life is regulated by the Internet search engines. Accordingly, the index hit the PC becomes a matter of vital importance, as there misses or departure from the index to become a serious problem. Let's start in order. Suppose your website is ranked in the index. The reason? There may be more.
- You incorrectly prescribed robots.txt file and accidentally close to index the entire site;
-You bought b / a domain that has already imposed its sanctions PS.
, Your site is in the blast zone, which search engines do not like domestic production;
-Fails at your hosting at the time, when he was visited by the crawler;
- Low-quality content (unreadable copy-paste);
-You have a virus is found on the site. More details can be found in the article as a reference check for viruses online.
-You have created a doorway, links and message board. Search engines do not like the sites.
-Your content is stolen, the thief and the site has been indexed first. This is worst of all. In this case, as you know, in the eyes of the search engine you are a thief, because his site was in the index first. To do something in this case is very difficult. The only way - to write a letter to the owner of a site that has stolen your content (helps very rare), or write directly to his hosting provider (it helps the bowl) so that his website simply disconnect from the network.
Also recommend reading the article - what if the content is stolen.
If you double checked your site and still have not found the reasons, feel free to write a letter to support the search engine. As a rule, it all worked out, or at least, would be called the cause. Knowing the cause is almost always possible to fix the problem.
In the next article, I think to look at the problem from another angle: how to prevent indexing of your site? From the point of view of any webmaster sounds blasphemous :) You think so? Then you have to read it :)