This site receives a lot of traffic. Even if it wasn't submitted, it would get noticed by the volume of traffic that it receives. A small, un-noticable business site would want to make sure that they were submitted to the major engines, but once the ball is rolling, it's more about traffic. If this site was not receiving much traffic, and therefore little content change between visits from the Google crawlers, it would have been put on , say, the six month indexing list, leaving it down in search result pages.
Fortunately, it gets the traffic to get found, to allow me to have questolo troubleshoot my PC problem and visit, now, daily, creating more traffic......etc., etc.
Keep up the good work, guys!
Jim