When building a website in the past, I have always used a directory for every page, and then named the page index.html so that to reach the page all that was needed was to type the directory name after the domain, for example:
www.mysite.com/tour
instead of
www.mysite.com/tour.html
Does this have any negative effect on SEO? When the SE crawls the site, does it rank lower a site where every page is called index.html?