As far as voting, looking at the 2016 election is selective bias. The fact is that young people have always lagged behind older folks when it comes to voting.
But Millennials seem to be voting in higher numbers than Gen Xers when they were the same age. Notice the jump in voter participation among 18-29 year olds in 2004, the first election millennials could vote in.
As far as experiences and social sharing, that's really just a matter of technological availability. Gen Xers and Boomers lugged around massive cameras and camcorders on every vacation, and you can bet they'd have shared all of that on social media if it was around back then. It's no surprise that Facebook activity skews older.