Thanks to all comments.
In my place they are actually illegal by law, but still in operation until now - i heard that the rule might be replaced with a new one which will accomodate them.
Here they are liked by many cab user mainly because of the short waiting time.
How they affect the existence of the conventional taxi cab service in your place? Here they mean a hard punch.
Rather unfair business fight i think, those new online taxi service (they call it ride sharing service) do not invest on car, do not do car maintenance, etc, etc...
So, the conventional taxi company will need some help to survive or even win against their new rival...