Bob Barr got 0.4% of the popular vote in 2008. Gary Johnson got 0.98% of the popular vote this year. He got over 3% in his home state of New Mexico. Many people I talked to said they'd like to vote for him, but were voting for Romney because they wanted Obama to lose, even though they didn't agree with all of Romney's platform.
I think many more people would have voted for him had the media portrayed him as a viable candidate. Why not include the major third party candidates in the debates? The presidential election system in this country is controlled by the major parties.