Have had a look around and saw lots of different values for rlz= Both http://www.google.com/search?hl=en&lr=&rlz=1B2GGFB_enEG203&q=test&btnG=Search and http://www.google.com/search?hl=en&lr=&rlz=1T4GWYE_en___US202&q=test&btnG=Search return the same but with different rlz values.. Looks like its related to Language or something ..... Hmmm am curious now..... Sorry I cant help! Will keep an eye on post to see if anyone else knows.. not that its life changing or anything... Good Luck!
Hey Sim and Sparks, I ran into the same problem trying to figure out which clicks were organic and which were PPC. Turns out the issue is Google Chrome. Here's my full post about the &rlz= Parameter: Organic or PPC.