Characteristics are used to identify and group objects in the ITP/MDK Repository. Characteristics are defined in projects' level Configuration. Once defined characteristics can be assigned to all underlying objects.
There are two kinds of characteristics: individual characteristics and grouped characteristics.
The difference is that you can determine by a setting in the New group or Edit group window, that from a group only one characteristic may be assigned to an object. This gives you some control over the assignment of characteristics.
Characteristics can be used in a Search action. Revisions of objects are not searched. Text Blocks, Forms, Views and Fields Sets cannot be searched (yet) as well.