There are a lot things that I have noticed not just about the 9/11 the Truth movement, but the people in the movement itself.
So here a five things I've noticed about people in the 9/11 Truth movement:
5. They're not who you think they are.
Back a few years ago I use to think that 9/11 Truthers came in three different flavors: Those on the extreme left who were suffering from Bush Derangement Syndrome, those on the extreme right who greatly distrust the government, and paranoid kooks who may be mentally ill and willing to believe in just about any crazy theory, but over the years I've found people who do not fall into any of those categories, and are actually perfectly normally people.
Heck, a few months ago a friend of mine posted something on their Facebook page in which they implied that the towers were brought down by explosives, and I was very shocked that they believed that. In fact I had actually thought that person's page had been hacked, but it turns out it wasn't, and because of that it's made me rethink that maybe not all 9/11 Truthers are a bunch of cranks, just misinformed. Some of them might even be to afraid to express their beliefs for fear of being labelled a crazy person.
4. They keep using the same, dis-proven theories.
Go to any site that promotes 9/11 conspiracy theories, or talk to anyone who believes in some of the 9/11 conspiracy theories, and you will get a variety of theories (technically speaking they're actually hypothesis) that despite their beliefs, and despite how much they seriously believe them to be true, they have been dis-proven and debunked, yet they still keep promoting them.
Apparently they must live belief that if you say something that isn't true enough times it will become true.
3. There is a lot of infighting.
While most people who promote certain types of conspiracy theories are normally united if they promote different theories about certain events, the same cannot be said about people who promote 9/11 conspiracy theories. This may be due to shear fact that unlike many conspiracy theories, 9/11 conspiracy theories varies greatly. Because of this members from one group promoting one theory might fight with members from another group promoting a different theory, with the two groups eventually accusing each other of being dis-info agents.
In the skeptic community this is generally referred to as "nutter fights"?
2. They always claim to have "undeniable evidence."
If you do a search on any major website using the words "9/11 Truth" you are going come across some pages that claims to have "undeniable evidence" or "undeniable proof" or something of the like that the 9/11 attacks were a false flag attack.
These claims in the end tend to prove absolutely nothing, but people in the movement still make them.
1. They don't want to do any real research into their own claims.
Probably the only reason why currently the amount of people that believe that the 9/11 attacks were committed by the government is above 10% is because the people who believe in it after all these years isn't because of some mental disorder, it's because they haven't done any real research for themselves, and have only relied on web sites and videos that promote the theories that they believe in.
In fact on the occasions when a a person who is a 9/11 Truther does real research on their own, and not simply rely on what some other 9/11 Truther says, they tend to leave the movement.