TheMadScientist - 7:39 am on Jan 22, 2013 (gmt 0)
Totally with lucy24 on this...
Why not just use PHP (or whatever) to grab the referrer when a visitor lands and not worry about putting it in the URL? The only way you shouldn't get it is if the visitor has set their browser to not send it (unlikely) or they're coming from a secure site.
If you're putting them in first (meaning the referring site links to something like example.com/somepage.ext?ref=WeReferredSomeone), then personally, I'd seriously considering running them through a PHP redirect that strips the parameter out of the URL and stores the info in a DB and cookie ... Please, keep in mind, I am a bit crazy, so it might not be the 'absolute best solution for search engines', because you lose a % of PageRank through each redirect (Oh, No!), but sometimes I try to not care about them so much and don't want a tacky looking url for visitors, which is what you end up with, in my opinion, if you don't strip the query string and store the info in a cookie 'on the way to the page' via PHP or some other scripting lang.