This is just indicating that these fields are dimensions. You can alse set fields as measures:
/* To indicate to QlikView that fields are dimensions */
TAG FIELDS field1, field2 WITH $dimension;
/* To indicate to QlikView that fields are measures */
TAG FIELDS field3, field, 4 WITH $measure;
Doing this you are helping your report users to identify visually in QlikView what is a dimension or measure when they are building charts, etc.
I'm also tring to get a grip of this, as it is not explained in the QV Reference manual.
As I understand from the Help you could just as well set all the tags in Document Properties->Tables also.
Can anyone explain the meaning of the custom tags "SalesRep", "Customer", "Time", "Sales" and "Product" added to some fields in the Whats New in QlikView11 app?
Do they have any practical value?