Does anyone have an idea how many professional Rails developers are out there at the moment? Is it tens of thousands? Hundreds? I know it is way more than thousands, because RailsConf sells out every year, and that's just the US. I'm procrastinating from writing a proposal, where I want to give a rationale for using Rails, and the width and depth of the developer community is a tremendous selling point. I'd like to quantify it without completely making something up.