Imagine that the field properties contains "Remember old data" checkboxes with several options;
Since this is a field property, Notes will create a special field behind the scenes, for example on the format;
$History<original field name>
The content in this field is controlled from the options above, but will for example contain data on the format;
<timestamp>|<user id changing the data>|<original data>
20080129T07:00|Bob Voith|This was the original data in the field
20080129T08:30|Roger Johannessen|This was the second edit in the field
This feature must of course be configurable, and by default OFF. Perhaps there should be some limitation parameters in the config too.