Wikipedia
alt.tv.simpsons (called "a.t.s." by regular readers) is a usenet newsgroup dedicated to discussing the American television program The Simpsons. Created in 1990, the newsgroup became a popular community in the early 1990s, and continues to exist as of 2014. It is known for reviewing episodes and nitpicking minor details on the show.
The writers of The Simpsons know about the forum and have on several occasions read the comments made on it. The character Comic Book Guy is often used in the show to lampoon and respond to the newsgroups fans. In interviews some writers have admitted that they do not like being scrutinized, but other writers have participated in the discussions on the forum. Independent commentators call the forum an example of an "active audience" and have claimed The Simpsons is tailor-made for such a forum.