Google Operating System spotted that YouTube is now offering search suggestions on their international sites. For example, if you go to YouTube UK and starting typing in a search phrase into the search box, YouTube will begin to offer you suggested results, much like Google does at Google Suggest.
Here is an example of beginning to type in my name:
As you can see, it doesn’t show the most results at the top but rather sorts it some other way, maybe by search volume? Does Google Operating System use a Google function to return the suggestions, e.g., http://suggestqueries.google.com/complete/search? hl=en&ds=yt&json=t&jsonp=callbackfunction&q=QUERY.
In any event, you can disable this feature in the “Settings” area.