We currently run www.FlagsExpress.com. It is way outdated, so we are redesigning the entire site using Volusion.com. The new site will go to the same domain, however all the URLs will be different, as the site content is set up very differently through Volusion than what we currently have. What precautions must I take to make sure that our new www.FlagExpress.com site is SEO friendly, keeping in mind that we are shutting down the old one and launching this completely new one. Do I need to worry about "content duplication"? Is there anything I can do about the fact that many of our customers have specific links bookmarked on their computers and once we re-launch those links will all be dead?

Any advice is greatly appreciated. Thank you