[There are many Democratic analysts and Republican analysts spouting off about the election. I figure why not a Libertarian one?]
The Boston Globe gave Libertarian candidate, Joe "No Relation" Kennedy, almost no coverage at all. For instance, when he took part in a televised debate involving all three candidates, he received a one-line mention the next day. It was the same with many news sources and media outlets in Massachusetts. While it was not unanimous dismissal, it was widespread.
If the same outlets that ignored him so mightily had, instead, built him up as even marginally viable, he might have drawn enough votes from Brown to have given Coakley a fighting chance. Instead, he was treated as though he didn't exist, and this cost the liberals.