With all the recent discussions about tracking users in the cellular market, it seemed a pretty strange coincidence that today I ran into a problem with my own attempts at privacy and cutting down tracking on the web.  Though my situation was with my desktop web browser, not my mobile phone.  I run IE9 on my Windows 7 systems, and went to a web site today and it didn’t render correctly which seemed pretty unusual since it was a site that I’m sure was supposed to support IE users.  So I checked it with the latest versions of Firefox and Chrome and it looked fine, went back to IE9 and again, it looked terrible.  The site even had a meta tag for IE9 to render in standards mode, so I was a bit baffled why it was doing so poorly.  I went and tried it on another system I have and it was the same.  Then I tried it on a third system, one that my wife uses and it looked fine.  I was really getting puzzled now, so I emailed a colleague who has done a lot of IE compatibility work and asked what I should try next.  He checked the site and said it looked fine for him, and suggested I turn on debugging in IE9 (you know, F12 debugging tools, which are great) and see if there are any errors.  Right away I start to unravel the mystery.  I see a file named http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js that is being marked as being blocked due to Tracking Protection.  And right after that log entry the page throws a script error: “jQuery is not defined”.  It turns out that Tracking Protection was blocking a script file that the page relied on.  I checked my IE9 settings and found I did have a personal tracking protection file in place.  I barely remember adding this, but I think I did back when IE first began to support it, and it was before any of the lists that are now available were published (look here to get a list from a selection of possible lists: http://ie.microsoft.com/testdrive/Browser/TrackingProtectionLists/) so I think I imported a list that was at the time available from the web.  Looks like the list I had was a bit too restrictive.  So I disabled my list and imported the TRUSTe list and now the site looks like it should.  I had reimaged this system a while ago, but had migrated my settings over, which had originally been migrated from my other system, so I have to assume the tracking list came from my old system and probably has been there for a long time now.

So mystery solved, and lesson learned, be careful with my tracking list. And next time I find a site that doesn’t look to be working in IE9, I’ll hit the F12 key and check the debugger.  It really can help pinpoint a problem with very little work.