SEO tools and mod_rewrite were out for a while. They do amazing things, like enabling humans to have a crisp view about the contents of a link. Unfortunately, until IIS 7 Microsoft didn’t had nothing comparable as default, but some companies struggled to offer this basic service.The two options were the rather cheap IISRewrite and the free ISAPI Rewrite Filter.
Mr Thomas Deml, Lead Program Manager in the IIS team, responsible for Security, Performance, Shared Hosting, presents in his overview about how SEO can be added to your application in his breakout session in MIX 09
Come learn SEO best practices and proven techniques that can boost the position of a Web site in search results pages.
Instead of having www.blabla.com/index.aspx?q=cats you can create a redirect to same page, but have instead the link www.blabla.com/search/cats. This enables the search engines to operate more efficiently in serving their customers (which can be also your customers, by the way) more accurate responses to their needs.