I appreciate that there's never going to be a perfect answer for this, but I was wondering how far you could go, using PHP+MySQL to automatically flag/identify an individual who had two accounts on your website.
Say for example on this site, they could use one account to 'boost' the other accounts reputation - which would be a nono.
At the moment I have an IP field that is updated upon each login with their remote server IP, which is far from perfect. Are there any better solutions (aside from detailed logs and comparing trends between users' actions) that could give you a quick 'hint' at a glimpse to suggest that this might be going on by means of a more accurate IP comparison or something else?
Obviously, if the user REALLY wants to do this, they will find a way - but I want to find a reasonable solution to make it (at least) moderately difficult or frustrating for them to pull it off.
Many thanks