Board Thread:Off-Topic Discussion/@comment-5441128-20160913213841/@comment-27794543-20160915003552

I hadn't paid attention to any of those shows, so I wasn't aware of their histories. Reading Wikipedia: Wikipedia doesn't mention petitions in articles for those three shows (though the Jericho campaign sounds like a petition & Family Guy had petitions to block the show). However, since petitions are easy to create, I wouldn't be surprised if most recently canceled shows have petitions. Though, when a show is revived, it's hard to tell what was the deciding factor for network executives. So ... petitions don't hurt, but it's unclear if they do anything except help rally fan campaigns for network executives to ignore.
 * Family Guy was canceled in 2000 & 2002, but is still airing today. 2000 was a short cancellation & Wikipedia doesn't mention fan involvement. 2002 was a 'real' cancellation, but after reruns helped create a 'cult following', the show was revived.
 * Jericho (I'm assuming we're talking about 2006 series & not one of the other 3 series with the same name) was cancelled in 2007, revived, and then terminated in 2008. According to Wikipedia, fan campaign was a large reason for the 2007 revival.
 * Hannibal was cancelled in 2015. So far, no revival.

Check out wikipedia:Category:Television series revived after cancellation for a list of shows revived after cancellation.