How do I track a users original source?

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I'm a marketing guy and I love knowing where every user came from. Not just that, I love knowing where my best / most profitable users came from.

Each time a user comes to the website, I need to record in a separate DB table:

1. Where the user came from (referral source or direct, Google's URL parameters ?utm_source= & utm_campaign= etc)
2. What campaign drove a customer through to the website

I can then develop my own analytics and reporting to determine which campaigns: PPC, SEO, Social Media, GDN, banner etc... brought in the best users (based on their engagement with the site, i.e. their reputation in the system).

I can then identify the best marketing campaigns and the lowest performing campaigns and act accordingly to maximize marketing spend for promoting the Q&A forum.

I'm learning python now (I'm a PHP programmer) but I'm afraid there's allot I don't know; IDEs, Django, Git-hub etc and I won't be able to get the work I need done.

Is there anyone else that would like to encourage marketing functionality in AskBot or work with me on developing marketing, analytics tracking tools for AskBot? Marketing is a core area that's simply ignored and as a result most Q&As don't get critical mass and become stagnant and fail.