Absolutely, I was thinking this as well. Living in Canada at the moment, I see elements of this but seemingly not to the same degree. Back home in the UK, preaching isn't nearly as common either. This trend makes sense though when you look at just how many Americans identify as Evangelical Protestants (25% of Christians, the largest religious denomination in the country). Preaching your beliefs is a central tenet of American culture, and now we have social media to cater directly to that.