In no way is the following a scientific experiment of any sort, but just do the following =
1) Search "Obama supporter" and "Romney supporter" on YouTube. If you notice, nearly all of the videos are of Obama/Romney supporters acting like complete idiots in front of camera, having absolutely no clue what they're spouting nor why they have chosen to support their candidate-of-choice.
2) Now do the same with "Ron Paul supporter" or "Gary Johnson supporter", then proceed to scroll through as many pages as you wish and take a look at the videos that turn up. Mostly all videos are of well-spoken Ron Paul supporters being interviewed on talk shows, and/or videos of law-abiding Ron Paul supporters being unfairly bullied by the opposition.
This should give you a rough idea of what the intellectual demographic is like, and what type of people are attracted to Obama/Romney compared to those that are attracted to Libertarian candidates like Ron Paul/Gary Johnson. Accuse me of cherrypicking? Well again, this isn't supposed to be a scientific experiment, but it has repeatedly been brought to my attention that Libertarian-minded people, on average, are a lot more politically-informed than those of the Democrat or Republican mindset.
You will almost never hear of an ex-Libertarian supporter, while Democrat or Republican supporters seem to jump ship more often than they change their underwear.