Account owner's can setup custom fields to track any data that you like in its own field.
The four types are:
To setup or view your custom fields login as the account owner and click Admin > Custom Fields.
Two custom fields we recommend everyone tracks is closing date + commission.
Custom fields appear on the left side of the contact record under Background.
You can display custom fields on the People screen by clicking "Columns" button and ticking custom fields to display:
You can also filter and sort by custom fields on the People screen:
Please note that for sorting to work correctly, the custom field needs to have the correct type, for example a Birthday field needs to be setup with Date type, Commission or Number of page views fields need to be a number.