Before large software companies roll out new features to everyone, they usually do A/B testing to make sure everything is going to work alright and to compare usage statistics.

were in limited beta tests before, now generally activated.

In my country (Spain) they have been working like a year or so. I think more countries were used to test. In my limited experience (I don't use much fb) I don't see a lot of people really using it. It's about 80%-likes/20%-the new "emotions" that people use in posts.

I just got them today.