Tags can be used for regions, locations, moods, colors, product categories, countries .... almost everything. I Picturepark tags are saved in lists, so the individual list items are tags.
Examples of lists are:
Season (fields: name) *simple one, with just the name of the season
Person (fields: First name, Last name, birthday, department, title) *multi-dimensional as the name of the person is enriched with information about birthday and departmental information.
Department (fields: name, goals, manager, team members (linked back to Person))
Products (fields: Product code, product category, product price, reseller)