Are there any PHP tracking tools that can be used in conjuction with adwords to help work out the effectiveness of campaigns? Preferably opensource, but not necessary. So for example (the most basic) if I have 1 AdWords campaign pointing to : http://www.mydomain.com?campaign=1 And another pointing to: http://www.mydomain.com?campaign=2 Then using the software I can track the users who click thru on the ad, through being visitor, to who joined, and then ultimately, who purchased. Hope that makes sense.