Online Animation Communities

The Internet is rife with communities encompassing various topics and mediums, ranging from niche comic-book properties to history buffs. Animation has spawned different communities within the realms of anime, western animation, online independent animation, etc. The most known, or vocal at least, seem to be on Newgrounds and YouTube, in which the latter consists of YouTubers reviewing cartoons. What are the aspects of these communities who dedicate themselves to discussing cartoons? What types of people are involved, and how do they view and treat the subject matter they name themselves after?