I understand that this kind of identification cannot be 100% accurate, but example usage would be internet poll, to detect users that have already voted. Is user detection possible with browser sent details? And what kind of information I can get from browser with every request? If I add IP address or location for example town to this, then identification would be more accurate. Are there any possible downsides I should know about?
preguntado el 08 de noviembre de 11 a las 09:11
You should not rely on such information.
As I'm sure you are aware all of this information can be aun forged. As you can specify any request header at will (the request header contains IP, location, browser etc.).
You can use it as a poll, but you should keep in mind that the poll will never be 100% accurate.
If you want to know where the user is from make him authenticate in the site with a valid e-mail and set a cookie on his browser.
Another way to check a user's identity/location is using a paid identity validation service like URU for instance. Even this however is never 100% accurate.