In 'old' ecco we could use "."  or "*" in a date folder,  and upon entry of text (anytext) in the item,  the DATE would be filled in for that item.  
 
Not shabby.
 
 
 
With Slang we can do (very easily) two very cool  related things.
 
 
1) Fill in date (even date and TIME)  when item is created-- whether or not the item text has any value  (perhaps the item is a graphics clip,  or has no text but has other folders holding data, etc.
 
 
 
the rule: ++:+:now:
 
 
 
2) Fill in the date and time only when item actually has/is assigned  any text.
 
 
the rule: ++:+:now:ITT ~= "."
 
 
 
 
[to have rule apply only to TLI (top level items),  add "T" next to the +:now,  ie. "++:T+:now: "]