Parcel (Tax Key) Numbers can be of any combination of letters and numbers, dashes or dots (any punctuation will do), Left or Right justified, even decimal numbers. 

Parcels can be assigned to user-defined geographical sections, such as Wards or Books.

Assign multiple Customers to a Parcel, with user- defined Relationships, such as Owner, Agent, Receiver.

Assign multiple, user-defined Borders to a Parcel.
This gives you the ability to define Frontage, Sides or 'Work Locations' for Corner Parcels, Alleys, etc., with different Addresses.  You can locate any Parcel by any of the Border Addresses.  Each Border stores its own dimensions.

You can define and assign Bill Codes for each Border, to track charges to the Customer, or charges that might be the responsibility of the City, such as an Intersection or even City  owned property.

Parcel and Border Addresses use a user-defined Street file for uniformity.  Users can locate Parcels and Borders by Street.