Last Thursday Google pushed through an update to the ga.js script which drastically changes the way visits are measured. A session (remember: session = visit) is now defined by a series of interactions with the site which are separated by no more than 30 minutes and come from a single campaign source. You’ll notice that closing the browser no longer ends a session. This brings the definition of session in line with the common definition of a visit and gives each more accurate attribution information
This means that utmc is no longer used! At least, not for sessions. Of course it’s still written.
There shouldn’t be much to notice on a user/implementer side, but here are the variables included in a basic utm.gif request now:
utmwv=5.1.5& utms=1& utmn=711547657& utmhn=www.cardinalpath.com& utmcs=UTF-8& utmsr=1366x768& utmsc=32-bit& utmul=en-gb& utmje=1& utmfl=10.3%20r183& utmdt=Cardinal%20Path%20-%20Web%20Analytics%20and%20Data%20Driven%20Marketing%20%7C%20Cardinal%20Path& utmhid=821714650& utmr=-& utmp=%2F& utmac=UA-22022050-1& utmcc=__utma%3D142955815.1740018290.1311192831.1312310134.1313770301.5%3B%2B__utmz%3D142955815.1311192831.1.1.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B& utmu=qBAAAAAg~
utm.gif is pretty much the same as before (and really, why would it change). Hadn’t noticed utmu before (I dont think…) and the grapevine says that its used for internal Google purposes.
All in all this should be a pretty good change, making attribution of metrics easier and more accurate.
