Yahoo just announced its beta platform on siteexplorer called “Dynamic URL Rewriting”. According to their blog,

Today comes a new wave for search engines with the first-ever Beta launch of ‘Dynamic URL Rewriting’ in Site Explorer. The new feature provides the ability for site owners to alert Yahoo! of the dynamic parameters in URLs that they’d like Yahoo! to ignore, which we’ll then automatically rewrite accordingly. Try this out for all the cases where you’d want to use parameters in your URLs that don’t affect the content of your page, but that have other important uses.

Advantages have also mentioned on their blog and the scenario and creating a wider site coverage.

* A more efficient crawl of your site, with fewer duplicate URLs being crawled.
* Better and deeper site coverage, as we’ll be able to use our crawler capacity to find and index more new content on your site.
* More unique content discovered, as we’ll handle more dynamic parameters in your URLs (if you remove the content-neutral dynamic parameters).
* Fewer chances of crawler traps, or web page sets that can cause an infinite number of requests or a poorly constructed crawler to crash.
* Cleaner and easier-to-read URLs displayed in the search results.
* Better site ranking due to reduced fragmentation of links and anchor text to your site’s pages.

You can check this functionality if you log-in to your site explorer and click manage site, you can see a dynamic url’s tab as seen in the picture below,

you can find more information here. it is good to hear this move from yahoo on search engine industry. Competition is large and tougher and who will bring the most business for us, that is the choice.