I look at the Recommended section daily, and I find it very disappointing for several reasons:

  - the recommendations are very often not interesting to me because
    + they cater to the lowest common denominator (you won't believe these 10 hilarious fails, PewDiePie picks his nose, etc.)
    + I have already watched the video
    + a video has been in the Recommended section for weeks and I haven't clicked on it. What makes you think I'll change my mind after several weeks? If I don't click a video within a couple of days of it appearing in the section, it's a dud. Don't keep showing it
    + the video is from a channel I am already subscribed to. That's not a recommendation, it's trivial and not helpful
    + most or all of the videos in the section are sometimes matching the same key word. I once clicked on an Amy Schumer video, and for many days every video in the Recommended section was a Schumer video. This is terrible. The same thing happened after I clicked a Craig Ferguson video.

  - the feedback UI is not streamlined. I have to click through multiple menus to be able to say: not interested in this channel

  - there should be list of key words that I can specify where if the video matches one of them, don't add it to the section. Conversely, there should be a list of key words that when I specify them, the recommendation engine goes out and looks for videos matching them, and then adds some of them to the section

I love watching interesting and creative how-to videos (DiResta, Tested, etc.), but even after several years of watching them, the recommendation engine seems to not have caught on to that.

Is the deep learning approach already deployed for regular users? I have not seen a change in the quality of the recommendations.

Sorry to sound so negative, but I think this is a huge wasted opportunity. There is tons of amazing content on youtube, and it's often very hard to find.