It seems that it have made some change yes. Before the change in my promotion He was a bit put down saying he got more thumbs down then up. Although I would say it's too short time and was to few looking at that time to actually know if it was just a one timer or a natural cause so to speak.

I do believe giving thumb down to something is just not necessary, it is there sure and you can use it. But for what reason? If you don't like something because it's not your taste, no real reason to put the creator of it down and possibly make him/her feel bad about what's shown. Not only saying this because it's my son, I've never given thumbs down myself. Unless it's something really f'd up like some bullying or something like that.

Conclusion, I hope it did have given some or many a 2nd thought of when to thumb something down or not. :)