Why do search engines have problems with dynamic websites

1. Dynamic web page does not exist when search engine Robots are reading the pages.

2. The search engine Robots usually do not read character such as "?", "%", "$" "#", "&", "*", "!"

3. Search engines usually consider dynamic Website as never ending links.

4. Search engines robots will get stock in an infinite loop specially if the dynamic page has Session ID

5. As all the pages is generated through database, a dynamic page does not exist as a file on a hosting server, as a static html page does until the request comes for a page, when a crawler comes to the website, does not get that pages to crawl every time, so crawler avoid those pages next time to crawl.

6. Database generated pages URL is called dynamic URLs, dynamic URL is not easy to read by human as well as search engine spiders.

7. Dynamic site can dramatically reduce your visibility in the search engines. Even though some engines spider dynamic URLs, others still do not. Those that do spider them may still place artificial limits on how deep they will travel within such links.

8. Typically such pages have a question mark (?) in the URL (or not). When a search engine crawler arrives at such a page, it captures the content but halts immediately, and will not follow the links, because it sees ahead of it an infinite number of pages.

9. Even after you make these changes, there will still be time-outs (search engines time-out quickly), and the code is usually poorly written for the search engine spiders. The pages are usually all one template, making it difficult to add keywords and to modify each page for keyword frequency.

10. If you create a static doorway page with a no follow tag, you will be hard pressed to get your website listed with the same ranking as other websites with hundreds of static pages and optimized code.

11. Indexing the same dynamic page might overload the servers of the search engines and therefore prevent the search engines to present with the most relevant information in the fastest possible time.

Here is what Google says about indexing of dynamic websites-

Reasons your site may not be included: Your pages are dynamically generated. We are able to index dynamically generated pages. However, because our web crawler can easily overwhelm and crash sites serving dynamic content, we limit the amount of dynamic pages we index. (Source - Google Webmaster Central)

Here is what Yahoo says about indexing of dynamic websites-

Yahoo! does index dynamic pages, but to discover pages, our web crawler mostly follows static links. We recommend that you avoid using dynamically generated links except in directories that are not intended to be crawled or indexed and for which you have employed robots.txt exclusion.

Here is what MSN - BING says about indexing of dynamic websites-

Long Dynamic URL - Returns URLs from your website that has exceptionally long query strings. Long query strings can create an infinite loop for search engines due to the large number of potential combinations of parameters. Use this report to view the URLs that Bing has flagged as being potentially too long. You can then investigate ways to shorten them.