Webmasters tools showing : http://b.scorecardresearch.com/beacon.js
 

When I go to Google webmasters tools > Labs > Site performance

There are a few page speed suggestion....

When I expand Details and then expand "Enable gzip compression" I see this along with other stuff which I know what it is :

http://b.scorecardresearch.com/beacon.js (248 bytes)

I have a few forums and all the ones I checked have this and when I search in the source code it doesnt exist anywhere and I even did a template search but found nothing....

Anybody know what this is? And why is it there when I never added it to any of my forums?

Any help would be much appreciated.

Thanks