The Google spiders are not perfect. They sometimes see things that aren’t there, and this can hurt you if they report incorrect findings back to the head spider.
Internal links that are inconsistent when it comes to urls are the most common mistake that can lead to poor ranking. If I have a link to www.PetStyles.com/DoggieDuds.html in one place, and simply to PetStyles.com/DoggieDuds.htm in another, I know they both go to the same page on my site.
Unfortunately, the spider doesn’t know that, and may see these links as going to two separate pages with identical content. Hear that ugly sound? It’s my ranking, going down the tubes. We HATE duplicate content.
The fix is simple, fortunately. Adjust all your internal links to match, consistently using either ‘www.’ . Set up a permanent redirect, so when someone types in your site name, it automatically redirects to the www. version.
Avoiding the very appearance of ‘evil’ is important when it comes to Google. Another pitfall can occur if you purchase different domains. This is a sound practice to help protect your brand, but can lead to the same problem with ‘duplicate’ content.
Simply redirect all alternate domain names to your main company site. Some web hosts don’t provide a 301 redirect, but ‘park’ your redirected names and keep the user in the same domain.
This can cause you more problems, but you can get around it by getting a second web hosting account and implementing your own 301 redirect in the .htaccess file. You can ‘park’ all your alternate domain names in the redirected account, and visitors to any of them will be funneled into your main url!
Back to the internal links; it is important to watch your links from content you have put out on the web as well. Make sure all your inbound links are consistent in their direction.
Once you have cleaned up all of your links and redirected your traffic to show the spiders that you have no duplicate content, you will probably see your search engine ranking improve.