Change is the one true constant. Web sites should always be in a state of change in order to grow. However, change is a dangerous thing and if done incorrectly can actually hinder a site. One of the most common things I see especially after successfully optimizing a site is the following: The site starts driving lots of business and sales and someone comments that the site should look as successful as it is. So flushed with extra money and excitement the site owner decides to go ahead with a redesign. Within a few days of launching a beautiful looking site visitors drop, sales drop and money seems like a distant memory. Client wonders what happened?

The answer is simple…redesign + new page names = 404. A 404 error (page not found error) occurs when a page can no longer be found. Google will index a site and have cache copies of all your old pages and will visit them independently to see if any updates were made, when it discovers a page missing it records the 404 error. Too many 404 errors will negatively impact your rankings.

How 404 errors will negatively impact your rankings:

1) loss of SEO content: When page names change it means that the indexed pages that have established rankings will suddenly lose those rankings.
2) loss of page rank: Page rank or link popularity is not site specific. It is more page specific meaning each page in your site hold its own page rank value and can pass link power to other pages or sites. When many pages are lost it can result is a loss of page rank and kill the site’s overall ability to rank.
3) too many errors penalty: Google’s goal is to show the very best of the web. Site’s with many errors are looked upon unfavorably by Google and can be penalized.

Causes of 404 errors:

1) Deleting pages: Deleting a page will cause a 404 error because it could be linked to from another site or be cached in the search engine’s index. When the link is visited it will produce a 404 error message.
2) Changing page names: HTML is case and extension sensitive. Simply changing the link from home.html to Home.html or home.asp will cause a 404 error when someone tries to visit the old address.

How to fix

1) Hire a SEO: Yes, this is shameless self promotion, but the fact is getting an expert involved early can prevent these problems from ever happening.
2) Create 301 redirects: When you change page names you need to create a 301 redirect from the old page to the new page. This is done through the .htaccess file. I will blog more on how to create these redirects in an upcoming post.
3) Remove pages from site: If you are no longer using the page at all you can use your robots.txt to prevent them from being indexed.
4) Remove pages from the index: If you really want to completely remove all traces of a deleted page then contacting Google and you can submit a removal request.

If you have any questions about 404 errors or page not found errors, please feel free to comment below or contact me direct I’m always willing to help