It's a funny thing. I've been on various email lists since the mid-80s; I'm currently active on about four dedicated to discussions of different authors' books. They've all got a variety of people and it's been interesting to hear different viewpoints from people of different nationalities, genders, and opinions. For readers, book preferences can be an important part of identity, and so all of the lists tend to feature occasional discussion about how pleasant it is to talk to people with whom we have so much in common. It really is blessedly easy to hold a conversation among people who generally know what you're talking about, with whom you can use the shorthand of comparing things, people, or events to ones in books.
There is definitely a difference among the different lists, though. On one list and its offshoots, people may occasionally annoiy each other, but it's like being annoyed by your family: you know what they mean and why they think so even when you disagree. Even when it's an old gripe that's become as irritating as chalk squeaking on a blackboard, you're still squeaking in a common language and you can generally figure out their priorities and the bases of opinions.
Another list has a few people I'd love to meet for longer conversations, a few with whom I've got nothing in common but our favorite authors (these are not mutually exclusive categories) and a few with whom I've REALLY got nothing in common. There's at least two or three people there who I'd be happy just to listen to as they talked about their lives, because I could learn so much I could apply to mine. There are people there whose life choices and opinions are totally different than mine but who are good to learn from for just that reason, plus a high level of mutual respect. (A few in that category have journals listed there in my sidebar or one of my friends / buddies lists, as do a few with whom I've got a good bit in common.) Then there are some whose thoughts and priorities just totally baffle me, as I'm sure mine do them. In general on that particular list, I find them overly precious and twee and I suspect they find me abrasive and prickly.
Nonetheless, we clearly do have things in common since we like the same author (though we do have different favorites within her works -- one person mentioned loving what I think is her weakest book by far). I'm not sure what lesson is to be gained by this for me, except that presumably I should try harder to look for the common ground, love all my neighbors as myself, see the good in everyone .... sorry, it must be rubbing off. (It's probably telling that it took me another hour to come back here and write that I should also try to be less abrasive. ) I think the lesson would be a lot more interesting if I were an author, to see what a wide variety of people my stuff might speak to. How do you write to maximize that? Should you try or must it flow naturally? Do different levels speak to different people, or can very different people all appreciate the deepest level of a work? I'm thinking of movies here comparing Roger Rabbit and Harry Potter -- I think the former had different levels for different ages, while the latter has touched people of different ages in more or less the same way at least to some degree .... and I may have just answered some of my own questions.