Brown shirts?

I've been reading references to "brown shirts" on blogs lately (Lileks, ASV, etc). What the heck does this mean? Al Gore is mentioned a lot in connection. I missed something. Can somebody clue me in?

Update: Thanks to Karl, in the comments, I understand. He points to this Wikipedia entry that has the following definition:

Today, the term "Brown Shirts" has become part of every day langugage as a term to describe the extreme rank and file of right wing organizations. It can also mean an individual of a right wing organization who is seen as very narrow-minded and excessively loyal.

As for the context with Al Gore, I followed a few links and learned that Al Gore gave a somewhat impassioned speach this week to the American Constitution Society. The transcript is here (pdf). In the first part of the speech, he gives reasoned, and reasonable, arguments about what the founding fathers meant for the Constitution to accomplish and how the President should carry out his role. In contrast to that, he mentions examples of how our current President has distorted the meaning of the Constitution and, in his view, abused his powers. For example, labeling somebody as an "enemy combatant" and holding them indefinitely without access to a lawyer. I agree with this. I don't like some of the things President Bush has done in his term. However, then Al Gore starts to get a bit emotional and, in my view, a little illogical. He calls right wing bloggers "digital Brown Shirts" and goes on and on about the illegitimacy of the Iraq war and how Bush is lying to the people.

Alles klar?