The reason I'm so quiet is because I find everyone to be much more knowledgeable than I am and feel my contributions here would be insignificant.
Compared to most people here on most subjects I am probably an idiot.(some here would heartily agree), but I don't let that stop me. You can learn a lot by contributing the little you think you do know. Also, you might find a niche where you can contribute a lot. I tend to post mostly to the political and historical subjects, but do occasional have a point or two to make on the hard science subjects too.
Jump in the waters fine.
Facts don't lie or have an agenda. Facts are just facts