(Click to enlarge)
It has since disappeared (I believe) but what is it? Why is it there?
It seems likely someone accidentally inserted code we, the users, were not meant to see- and Youtube's twitter message about it was incredibly odd (see below.)
Is youtube beginning to track users? Is it some sort of accidental glitch related to government-mandated back doors to observe our searches and private content? Or was it some sort of bizarre experiment to see what kind of public outcry would be generated?
No clear answers at this point- and anyone holding their breath for google to comment must be a lunatic as they don't even listen to youtubers as to channel designs and more mundane content.