Who are behind Google Webmaster Forum?

Recently I asked and answered several questions on Google Webmaster Forum. I am surprised to see that some extremely active users are there to answer your questions. I am also surprised that those extremely active users are trying to do SEO in such a good conscious and aggressively advocating creating unique content in a natural way. What I am really curious is who they are, what they do for living, and why they are working so hard on this forum. It seems some of them stay online 7/24 to answer questions and discuss interesting topics. I am a webmaster and I am busy. Involving into one or two questions per day is already too much for me. How could you answer ten, twenty, or more questions and keep talking all day long? Thanks for them, I will go to Webmaster Forum whenever I have a question. :)