'Cause our movie's better than yours!"
Two long-running shows or two star actors inspire dueling fandoms. Fans of one are expected to become Fan Haters of the other, and vice versa. The contrasting merits of both will rarely be acknowledged. Anyone who likes both will be accused of Fandom Heresy. This can easily go on despite the creators' Word of God that they actually like the other show or the actors making friendly appearances together (Tabloid Melodrama aside). Of course there will be those who hate both.
In some instances, this is the result of a new fandom displacing an older one. For example, Henry Jenkins notes in his book Textual Poachers that the emergence of an American Blake's 7 fandom was ideally timed to capitalize on institutional conflicts within Doctor Who fandom (which shared its focus on a British series) and declining interest in Star Wars (which shared its interest in stories about La Résistance). This also happens when one show is perceived by one fandom as a rip-off of their favorite show.
It is of course, fully possible for die-hard fans of one "rival" show to enjoy another, and being a member of one fandom does not exclude you from being a member of the other. In some cases, this might lead to the rivalry eventually morphing into a case of Friendly Fandoms.
Ridiculously common in sports, due to real-life sports rivalries such as the Hamilton-Verstappen rivalry in Formula One, or Magic Johnson and Larry Byrd in the NBA. In the music industry, this trope is distressingly common with female artists. If two women of the same age and genre are making headway at the same time, the media will endlessly compare the two and fans will go on about which one is better. How the singers personally feel is never taken into account. In many cases the ladies are friends or at least have mutual respect, and have spoken on the sexism of constantly pitting women against each other. It's not unheard of for two "rivals" to record a duet specifically to prove that there's no bad blood.
In order for this to count, both sides needs to have their own attackers (bashing their rival show) and defenders (defending their show). Any lack of one element on both sides will make this no longer a rivalry.
Often involves Dueling Works. Compare Ship-to-Ship Combat. See Broken Base for when fandoms have civil wars amongst themselves. Contrast Friendly Fandoms. Often a real life version of Sitcom Arch-Nemesis. Usually features Ultimate Showdown of Ultimate Destiny.
Examples:
- Anime & Manga
- Automobiles
- Comic Books
- Films — Live-Action
- Inter-Media
- Literature
- Live-Action TV
- Music
- Sports
- Tabletop Games
- Technology
- Video Games
- Web Original
- Western Animation
- Other Media
- Real Life
