If you develop navigational menus invisible to search engines, think SEO is voodoo, recycle information from one client's Web site to another, create duplicate URLs for the same content, or bury important pages deep within your Web site, then you're engaging in some of the not-so-best practices that make Web site developers need professional SEO services. The above are just some of the 85 ways Web site developers keep SEO professionals in business, according to Jill Whalen.