Might sound noobish but I am trying to make a GPT script and I am having a little trouble setting up the postback script I am signed up at adscend media, redfirenetwork and adwork media My problem is getting a custom variable (User ID) to be forwarded to the postback script, I want to identify who completed the survey by the user ID's (that is in my database) and not their IP since they might change it. How do I do that? I asked support at redfirenetwork and adsncend media and they are totally useless when it comes to php so I am asking here if anyone knows. I was hoping it would be as easy as just adding ?uid=<?php echo $UserID; ?> to the survey URL but it seems thats not the case How do other gpt scripts do this? I was thinking maybe comparing the IP to last logged in IPs (since I am tracking that) and get the user ID from there but I am not sure how well that would be.. I am sure there someone here that can help me!