Dynamic pages are roadblocks to high search engine positioning. Especially those that end in "?" or "&". In a dynamic site, variables are passed to the URL and the page is generated dynamically, often from information stored in a database as is the case with many e-commerce sites. Normal .html pages are static - they are hard-coded, their information does not change, and there are no "?" or "&" characters in the URL.

URL rewrites are programming techniques that allow the returned URL to be more search engine friendly by removing the question mark (?) and ampersand (&) from the returned URL found in the location or address bar. This enables the search engines to index the page without having variables or session ids interlaced into the URL.

Pages with dynamic URLs are present in several engines, notably Google and AltaVista, even though publicly AltaVista claims their spider does not crawl dynamic URLs. To a spider a "?" represents a sea of endless possibilities - some pages can automatically generate a potentially massive number of URLs, trapping the spider in a virtually infinite loop.

As a general rule, search engines will not properly index documents that:

• contain a "?" or "&"
  
• End in the following document types: .cfm, .asp, .shtml, .php, .stm, .jsp, .cgi, .pl
  
• Could potentially generate a large number of URLs.

In these cases, where page should be dynamic it is possible to clean up their query strings. URL rewriting generally clean up ‘?’, ‘&’, ‘+’ symbols in URLs to more user friendly characters. Check out the following URL:
http://www.yourdomain.com/shop.php?cat_id=1&item_id=2

This dynamic URL can be converted into:
http://www.yourdomain.com/shoppinglist/apparels/shirts

This makes the page look static but in actual it is dynamic. URL rewriting needs some serious strategy and planning. There are few tools available fro URL rewriting. These are rule-based tools and the most famous tools are ‘More Rewrite’ for Apache and ISAPI rewrite for IIS.

Continue ...