Back to the point of this post, I think those of us here need to realize something very important that I've come to understand over the past few years. Most of us are out of touch with how ignorant the average person in the US is.
This is an important point.
I've learned over the last decade of being a physical anthropologist that most people who don't accept evolution are simply parroting what they were told in church. This is generally not an important issue to them; it takes a back seat to other topics like same-sex marriage and abortion. Most people I've met who initially espouse a young earth creationist view are quick to mostly abandon that if they're willing to listen and presented with facts in a respectful, non-confrontational view. That is, their belief that the earth is 4,600 years old is usually not strongly held.
If you want to convince someone that the earth is billions of years old, that evolution is real, and that we are still evolving, you have to do a number of things. First, you have to divorce evolution from other 'progressive' social viewpoints. Second, you have to illustrate how evolution is no more an affront to their faith than is heliocentrism. Third, you have to illustrate that evolution is useful and economically relevant. Fourth, and most importantly, you must refrain from attacking their other religiously-motivated views.