To hear The Guardian tell it, "Game of Thrones is the biggest TV show on television. It’s Dallas with dragons. It’s EastEnders with nudity. It’s The Apprentice with a very slightly more liberal worldview."
Wikipedia chronicles the show's success:
"Game of Thrones has attracted record viewership on HBO and has a broad, active, international fan base. It has been acclaimed by critics, particularly for its acting, complex characters, story, scope, and production values, although its frequent use of nudity and violence (including sexual violence) has been criticized. The series has received 38 Primetime Emmy Awards, including Outstanding Drama Series in 2015 and 2016, more than any other primetime scripted television series. Its other awards and nominations include three Hugo Awards for Best Dramatic Presentation (2012–2014), a 2011 Peabody Award, and five nominations for the Golden Globe Award for Best Television Series – Drama (2012 and 2015–2018).
Of the ensemble cast, Peter Dinklage has won two Primetime Emmy Awards for Outstanding Supporting Actor in a Drama Series (2011 and 2015) and the Golden Globe Award for Best Supporting Actor – Series, Miniseries or Television Film (2012) for his performance as Tyrion Lannister. Lena Headey, Emilia Clarke, Kit Harington, Maisie Williams, Diana Rigg, and Max von Sydow have also received Primetime Emmy Award nominations for their performances."
Fandom chronicle FanSided, which puts together a 250-strong list of the best fandoms in existence, drawing from the worlds of sports, movies, celebrities, TV and more, gave Game of Thrones fans the #2 spot in 2018. "They’re the fans that have made the show a worldwide crossover hit in an age where TV audiences are getting smaller and more segmented. They’re the fans who put together an epic convention that celebrated both the show and the Song of Ice and Fire series by examining it from every angle imaginable — as an academic subject, as a rip-roaring yarn, as a social document, as an inspiration for cosplay, and so on. They’re the fans who travel far and wide to see the locations where their favorite scenes were filmed, to the point where they’ve boosted the economies of certain countries," an article on the 2018 FanSided list announcement read.