It’s no shock to anyone even remotely up to speed on popular culture that YouTube is big. Really big, in fact. But even big can get bigger, as evidenced by a recent press release pushed out by comScore. For the first time in a single month, YouTube had over 100 million US viewers, with the online video portal securing a staggering 91 percent share of all videos watched online during the month of January 2009. More specifically, some 14.8 billion online videos were watched by Americans, which was up 4 percent