There are a number of things that have a direct impact on your performance in search engine results. However, some of them can do much more than limit your performance, they can actually sabotage it entirely.

The following are the top 10 methods of sabotage that you can inflict on your Web site, whether consciously or subconsciously.

1. Robots.txt

The robots.txt is a great tool to identify sections or pages within a site that search engines should not crawl or index. Incorrectly building this file can exclude your site from search engines and their results pages.

2. Cloaking

Delivering different content to search engine crawlers than what is given to users is sometimes necessary. However, implementing this improperly is called cloaking and considered a black hat optimization technique. Search engines can penalize your site significantly for improperly presenting different information to them.

3. Logins

Content that is only accessible after logging into a Web site cannot be seen by search engines. As a result, these pages will not show up in search results. If you must require a login to access areas of your site, make sure you have at least a few pages that explain what you offer. This provides an opportunity for these pages to appear in search results.

4. Flash Only Site

Flash is a very useful tool in providing a unique experience to users. Nevertheless, when a site is built completely in Flash, text and links are currently not accessible to the search engines. If you build your entire site in Flash you are shooting yourself in the foot in terms of organic search rankings.

5. Site Architecture

How you build your site and how users navigate it can have a profound impact on the way your site is indexed and ranked. Hierarchies and navigation are extremely important for search engine crawlers. Without being able to find all of your pages, they cannot accurately rank them in search results. Don’t burry all your pages deep under levels of directories. A flatter site structure is smarter for search. Also, use internal linking and sitemaps (html and xml) to help the engines find all your site pages.

6. Inline JavaScript and CSS coding

JavaScript and CSS are powerful developer tools to control and monitor the user experience of a Web site. Code is important and has its place.  However, it should be placed in a control file and called when needed instead of being placed on individual pages whenever possible. When page code is filled with script, it makes the page load slower and encourages the search engine crawler to abandon indexing. Keeping your pages light on code will enable whole pages, and more pages, to be indexed at a time. 

7. Over Optimization

Over optimization is the process of trying to be everything to everyone on every page of your Web site. If you cover too many topics per page, and jam keywords into those pages, the content won’t read well for users or the search engines. Instead, create individual pages to cover each topic, and choose a handful of keywords to target per page. Ensuring you have the right balance and focus throughout your site is important for search engine rankings and to provide a quality user experience.

8. Sessions IDs in URLs

Sessions are used to monitor users as they navigate through a Web site. Session IDs and other variables can confuse search engines. This can make it appear that your site contains duplicate content, thereby diluting the authority and relevance of your site.

9. Constantly Moving Content

Search engines are always hungry for new content, but moving content continually can lower the value of your content. Like a fine wine, pages can get better with age, but when you move content from one page to another it starts the aging process all over again.

10. Server Speed and Page File Size

Page file size and server speed are important factors for a positive user experience.  Users (and crawlers) don’t like to wait for pages to load. Loading speed is becoming a factor in search engine rankings and should be a consideration for users as well.

These are the top 10 ways to sabotage your Website. However, there are a number of items that didn’t make the short list. Nevertheless, one thing is important to note: Many of the identified activities above can be very useful and are necessary to the health and well being of your site.

As with most things in SEO, proper implementation of best practices can have a great impact to your search engine rankings.