Ron Paul didn't pull votes from McCain, but he had many supporters that ended up voting for Obama. There is a large segment of people that would prefer libertarian-conservatism, but would never vote for McCain because they believed he was a continuation of Bush.
To put things simply, they would rather have Obama than McCain, but have very conservative economic ideas. This is because both are relatively pro-big government/spending.
It's no secret that there is a tremendous amount of conservatism among the youth on the internet, and the country as a whole. However, the next generation of voters are much more liberal on issues such as gay marriage and abortion, but a lot are very fiscally conservative. That is the direction that political opinions are heading, and that is the way that the party must go.
The Republican stance on social issues is quickly becoming less and less prevalent among the population, however the disgust with the trillion dollar deficits is growing exponentially. The Republican party must take on more libertarian ideas if it wants to return to power.