When navigating from one page to another on YouTube, it shows a thin red loading bar at the top of the screen. I didn't even notice it before someone pointed it.

What UX factors could have gone into the decision to use such a loading bar?

closed as primarily opinion-based by ChrisF, Graham Herrli, Benny Skogberg Mar 4 '15 at 6:50

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.


The moving bar indicates that some sort of validation is happening before the video can be served.

validation bar

Since YouTube content is constantly being updated or even deleted by the users who created it this process can provide better information in failure cases.

validation error

On slower connections it tells the user "preparing next video, hang in there" and keeps people sticking around on the page longer if nothing else than to question "I wonder what that red bar is doing?"

On a fast internet connection the validation is so quick that YouTube should probably wait at least a second before even showing it to begin with.

  • It seems like the bar also just shows up when data is loading not just validation. This happens for instance when you go from the home page to subscriptions. – bigblind Dec 18 '14 at 9:58
  • I would have put this into my previous comment, but they can only be edited for 5 minutes. dropbox.com/s/j9zbk6wfkhlrmyg/youtube.gif?dl=0 – bigblind Dec 18 '14 at 10:04

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