1. A method comprising: detecting fraudulent clicks performed towards an on-screen advertisement; wherein the detecting comprises: (a) presenting to a user of an electronic device, a screen comprising content and said on-screen advertisement; (b) injecting a temporary input/output interference that causes an on-screen pointer, that is on route to click within said on-screen advertisement, to exhibit irregular behavior from its regular route; (c) tracking user interactions with said input unit in response to said temporary input/output interference; (d) determining that said user did not perform sufficient manual correction operations that fix said temporary input/output interference; (e) based on step (d), determining that a click performed within said on-screen advertisement, was performed by a click-fraud mechanism.