Rulings
10/1/2005 
The tokens and counters that Doubling Season creates are exact copies of the kind of tokens and counters that were being created in the first place. 
10/1/2005 
Doubling Season affects cards that "enter the battlefield with" a certain number of counters. Triskelion, for example, would enter the battlefield with six +1/+1 counters on it rather than three. 
10/1/2005 
If there are two Doubling Seasons on the battlefield, then the number of tokens or counters is four times the original number. If there are three on the battlefield, then the number of tokens or counters is eight times the original number, and so on. 
10/1/2005 
Planeswalkers will enter the battlefield with double the normal amount of loyalty counters. However, if you activate an ability whose cost has you put loyalty counters on a planeswalker, the number you put on isn't doubled. This is because those counters are put on as a cost, not as an effect. 
