Overview of 301 redirect
The code “301″ means “file moved permanently”.
A 301 redirect is implemented in your .htaccess file. In the .htaccess file, after the code, the URL of the missing or renamed page is noted, followed by a space, then followed by the new location or file name.
A 301 redirect is the most efficient and spider and visitor friendly strategy around for web sites.
Why you should consider using 301 redirect for site relaunch
It’s easy and simple to set up 301 redirects and it should preserve your search engine rankings for that particular page. If you HAVE to change file names or move pages around, it’s the safest option to redirect pages without impacting your page ranking.
A lot of site lose out on valuable search engine traffic due to incorrectly configuring the redirects. It is very import that when a search engine comes to crawl your website it is able to follow any redirects you have set up.
Suppose you have a website http://www.xyz.com and you create a redirect such that whenever any visitor types in the URL http://www.xyz.com he is automatically redirected to http://www.xyz.com/abc/, If the Search Engine is not able to follow the redirect it would think that http://www.xyz.com has no contents, http://www.xyz.com would end up ranking very badly in search engines.
Common way to track it through web analytics
I track my 404 error page by adding the google analytics tracking code in it.
I remember at one point, I updated all of my URLs to reflect best SEO practices by replacing URLs that contain “_” to “-”. However, I missed out several pages, so I carefully looked at what pages resulted in 404, and added the new page URL to the 301 redirect.
This is one way you can leverage your analytics and error pages to make sure all of the page requests are redirected to proper page URLs.