Reading Sheldon Brown's writings on fixed gear was a major influence on me.
I love bikes, and started thinking about building a single speed road bike for the elegant simplicity of it. I think it was stumbling upon Sheldon's writing about fixed that first made me aware that it was even an option. I WANTED to try a fixed gear bike before I committed to owning one, but they are not at all common around here. With the hook set the idea kept recurring in my head until I couldn't resist it any more.
I never read a single post about fixed gear bikes on an online forum until I had already decided to start building one. That was when I came here and tapped into the collective knowledge to help me build a bike I would actually want to ride.
This forum has been a great resource, and it did influence my decisions about things like component choice. I was looking for low cost, and high durability/reliabbility, and the input of experienced and knowledgeable people here has been a great resource, but never influenced my decision to ride fixed.
Another factor that made ME want to ride fixed gear was actually the spinning classes that helped me get through the winter last year. I don't know how many here are familiar with spinning bikes, but they are more similar in feel to riding fixed than freewheel. that's because you are driving a large metal flywheel with no freewheel to it. The momentum of the spin is the same feel as riding fixed, and more than any other factor it was the desire to get that sensation on a road bike that inspired me to want to have a fixed bike. I would also say spinning bikes are good for training in the same way fixed gear bikes are, and they are also great training for riding fixed. When I had built my fixed bike it took very little adjustment to get used to riding it.
I've never heard of anyone else being influenced by spinning class to ride fixed, but it did it for me, and a girl in my class is now building a fix as well.