I need to know if there is any way to uniquely identify a mobile device through a mobile web browser on the device. Is there some portion of the UserAgent string that would allow me to see some sort of unique ID (i.e. IMEI, ESN or SID and Serial).
I know there are privacy concerns with this, but I don't need the cell number or anything to identify the end user, I just need to be able to track if a device has submitted information to my web site (I need to limit this so information can only be submitted once per device).
I have thought about cookies, but I would like something more reliable. Cookies can just be erased and then the device would be allowed to submit informaiton more than once.
Also, I think the majority of the devices visiting the site will be Windows Mobile devices, so even if the solution is specific to Windows Mobile, or Internet Explorer Mobile, that would probably be acceptable. (Could be multiple versions of the OS on multiple carriers, so it would need to be carrier independent and work on Mobile 5 or better)
If anyone could offer any advice, I would greatly appreciate it.