SEO Glossary

Search Engine Optimization (SEO) is not only a complex task for SEO professionals, but is also a subject that remains vague and unfamiliar to those who are interested in search engine optimized contens produced by themselves or their ghostwriters for publication on the web. The primary goal of this SEO Glossary is to make seo terms understandable to persons who are not professionals of SEO or Search Engine Optimization.

200

Status OK - The server returns code 200 when a file request was successful and a page or image was found and loaded properly in a browser. 
 

301 Redirect

A 301 redirect means moving a page to a new location, permanently. It tells the search engines that if e.g. a site A or page A has been 301'd to site B or page B, then it is intended that the site or page B shall appear in the search results and the site A or page A will be permanently removed from the results.  

The 301 redirect is required for preserving existing page ranks and for preventing page rank splits as described below:

New Top Level Domain: If, for some reason, one is thinking of changing the main domain, 301 redirect is essential  
to send traffic from the old site to the new site. Without a 301 redirect the new site will be a considered by search engines as completely new and any historic profile created by a search engine, including the page ranks, will not be carried over to the new site.

Page Deleted or Moved: A common use of 301 redirect is pointing to a new page when the content of a page is no more relevant. 

WWW vs Non-WWW: By using a permanent 301 redirect to send traffic destined to the non www version of a site (site.com) to the www version (www.site.com), one can prevent page rank split between the two variants, giving the home page and internal pages some extra page rank juice.

Creation of a 301 redirect is not quite simple because special commands are required in the .htaccess file if Apache server is used. In case of Windows servers, creation of 301 is even more complicated. This task should be performed by experienced webmasters. That's why people often tend to mistakenly use 302 instead of 301 for redirection.

302 redirect

302 is a temporary redirect telling the search engines to keep the old domain or page indexed, but also to index the new one.

400

The server returns code 400 when it could not locate the requested URL.

.htaccess

Apache directory-level configuration file used to password protect or redirect files. Any manipulation of this file needs extreme caution.