Many webmasters don't get high rankings on Google and other search engines just because Google's indexing robot has difficulty to index their web pages.
Search engine robots are very simple software programs. If an indexing robot cannot find the content of your website immediately, it will skip your site and go to the next link in the list. For that reason, it is very important to make sure that search engine robots can index your web pages without problems.
Here are the top 5 elements that drive search engine robots away:
Reason 1: Your robots.txt file is damaged or it contains a typo
If search engine robots misinterpret your robots.txt file, they might completely ignore your web pages.
Double check your robots.txt file and make sure that you use the disallow parameter only for web pages that you really don't want to have indexed.
Reason 2: Your URLs contain too many variables
URLs with many variables can cause problems with search engine robots. If your URLs contain too many variables, search engine robots might ignore your pages.
Here's Google's official statement about web pages with many variables:
"Google indexes dynamically generated webpages, including .asp pages, .php pages, and pages with question marks in their URLs. However, these pages can cause problems for our crawler and may be ignored."
Reason 3: You use session IDs in your URLs
Many search engines don't index URLs that contain session IDs because they can lead to duplicate content problems. If possible, avoid session IDs in your URLs. Better use cookies to store session IDs.
Reason 4: Your web pages contain too much code
Of course, your web pages can contain JavaScript code, CSS code and other script code that is not directly related to your content. Visit your website with a web browser and select "View source" or "View HTML source".
If it is difficult for you to spot the actual content of your website then search engines might also have difficulty to parse your pages.
Reason 5: Your website navigation causes problems
Fancy JavaScript or DHTML menus cannot be parsed by most search engine robots. Flash or AJAX menus are even worse when it comes to website navigation.
As mentioned above, search engine robots are very simple programs. They can follow HTML links, all other links can cause problems.
Optimized web page content and good inbound links are crucial for high search engine rankings. However, the best content and the best links won't help you much if search engines cannot index your pages.
Make sure that search engine spiders can index your web pages without problems so that your web pages can get the rankings they deserve.
