I am creating a CMS and which creates profiles for widget salesmen. Customers purchase these widgets locally. Each time a profile is created a new salesperson enters their city, state and zip along with relevant details. A new subdomain is created for each city, ie chicago.widget-sales.com or houston.widget-sales.com. Customers can search their local neighborhood for people who sell red-widgets, green-widgets, and black widgets. Salespeople can offer all 3. When a user performs a search, an example of the next folder would be chicago.widget-sales.com/red and the relevant profiles will populate. Each salesperson will have a profile page ie chicago.widget-sales.com/red/001 in the relevant folder. If a salesperson sells green widgets and red widgets the same profile will appear in the green folder and the red folder. How can I take advantage of rel=canonical as to not get penalized for duplicate content? Is 301 a better option?