The American X Factor gets an average of 94,000 comments in social media per episode

"Fox's "The X Factor" is No. 1 among new series, with an average of 94,000 social comments per episode as recorded by Bluefin. It hasn't been the "American Idol"-killer that Simon Cowell obviously hoped it would be, but it's turned out to be a very solid hit for Fox. In fact, it's helping boost other shows on the network."

Source:  Data from Bluefin, reported by AdAge, 4th November 2011

Note - in the article 5 shows are compared, but frustratingly there's no direct comparison between X Factor and American Idol