When a form is saved, a user is navigated to a view page of the last saved node (‘View’ tab). It is necessary to make redirect to some URL.

When moving your site from one engine to another one, pages’ URLs are changed and you ma need to save oold URLs. First, there are links to these URLs from other sites, and search engines …

Site was available through sub domain (for example, its test version), and you need to move it to server root.  To avoid content duplicating (search engines don’t like this) you should canonize domain name (redirecting  …

When web site is under construction, it is often stored within subfolder of the existing site so search engines are able to index it. And after the site moves to server root all indexed links …