Nah, True Blood is fairly mainstream. It's a paranormal romance populated entirely by good-looking people with copious sex and violence and reasonably simple plots. These are all things that mainstream viewers love, and True Blood's numbers reflect that.

Game of Thrones is a gritty medieval fantasy political drama whose viewers actually requested less sex after the first season. Game of Thrones commonly features scenes of (for example) haggard old people sitting at a table talking about whether they'll go over a bridge or whether they should walk through a forest. It is probably the geekiest show I've seen on TV in my lifetime. Maybe ST:TNG beats it, but I'm not sure.