I have a requirement like this. My user can publish articles which are present in my website anywhere in the net. If somebody clicks on that link I will give my user points.
I have to uniquely identify the user machine so that if any body clicks the same post second time I will not give points to my user.
Using IP address we cannot identify, most of them are DHCP. Using cookies also we can't identify. Cookies are browser specific.
Is there any best approach to identify unique visitor machine.
I am using java 1.5