A lot of sites use an additive filtration system while there is also subtractive now is used.
A difference in an interaction method: Additive First of all you need to choose a set of the options necessary to you and call to filter button,
Subtractive This method based on consecutive liquidation of unnecessary results.
The additive model often conducts to a "zero searches" with a relevant data based on features of interaction of the user.
Why the additive form of a filtration is used everywhere, though subtractive leads to the necessary result much faster and there is no zero searches possibility?