When I reviewed Landline I mentioned how much I had loved Fangirl (which I had just finished reading). 
 I really identified with Cath, more than I identified with Eleanor (of Eleanor & Park), I think that's a skill of Rainbow Rowell's- making characters which are easy to identify with. 
 To me Cath was a Harry Potter fangirl, I'm not quite her (only the occasional dip into the world of fanfiction) but I certainly 'knew' people like her, and saw a lot of elements of myself in her. Harry Potter was a big part of my world for a while (which I have spoken about before), so I think I understood Cath, although maybe I was more of a balance between her and Wren when it came to uni. 
 Thinking about it, actually, Fangirl is quite a lot like 4 to 16 characters, although I did prefer it. 
 It's cute, and it's romantic, and it's real, that's what's awesome about it.