SharePoint crawling options provide the "Crawl complex URL" option, that applicable on the site with URL that contain a query parameter specified with a question mark (for example, www.mysite.com/list.aspx?item=1). Depending upon the site, these URLs might or might not include relevant content.
|Complex URLs can often redirect to less relevant sites, and it might be a good idea to enable this option on only sites where the content available from complex URLs is known to be relevant. But this option will applicable only for non-SharePoint sites.
This has no effect when crawling SharePoint sites, because Office SharePoint Server 2007 enumerates all content when crawling SharePoint sites, ignoring URL parameters.