I need to choose a marketing tracking software for my website that uses a signup/free-trial model, where users can later upgrade to paid memberships. Obviously I want to be able to measure each marketing campaign's performance in terms of clicks, signups, email-opt-ins, and conversions. I'm assuming solutions such as Thrive, Voluum and iMobiTrax all offer these features in their own ways. But how would it work in my case, where it takes users several log-in sessions to convert to paid members? I'm assuming I need to tag them with a campaign ID upon signing up, and then that tag follows them through their lifetime on my site, so if they convert several weeks later, I load a tracker with that same tag on the "Thank you for upgrading your membership page!" or something like that? Do any of the above software make this easy? Do any of you guys have experience tracking users through this free-trial business model? It's hard to find info since most examples are based on the ad immediately converting into a sale.