I have recently heard that there are some internet websites which give small commission to the user who have made account on that site and view the advertisements published by that site.
Is such earning halal?
it is haram if it is lying/cheating/fraud/deception against advertisers who pay money to advertisement system for real advertisement views or clicks or certain actions on target site or by target phone number. and advertisement system is also cheated because it is waiting for true views and clicks from the sites which publish the ads. this site takes money from advertisement system but give false/artificial views, clicks etc to advertisement system.
but, if the site you are asking about is not using advertisement system and not cheating advertisers and the advertisers know how does it work, i.e. they intentionally pay just for any view by real human, it is probably allowed.