With poorly drawn diagrams.
Abstract things often have a spatial element for me. For example, the months of the year go around in a circle, clockwise. But I never see the whole circle at once, only the month I'm thinking about and the ones on either side.
Or this: when I first got onto LJ, it was unfamiliar and so in my mental monitor, it occupied the bottom right corner. Now that it's a comfortable place for me, it's moved to the upper left.
I was talking with laurashapiro about LJ and mailing lists and how fandom is different depending where you are and I started to think about how each of them feels to me, spatially, and how it's a metaphor for their function. (This seemed a lot more brilliant then -- I think it was the rum. But I press on regardless!)
I should probably be dealing with Usenet too, but I only ever hung out on alt.tv.x-files.creative. So I will simply say that being on a newsgroup feels to me like being outdoors and move on.
A mailing list, to me, is a sphere. A bubble. A discrete entity. Content flows into it, but doesn't flow out -- it's all in there and it doesn't mix with all the other mailing list bubbles. I go from bubble to bubble, depending on what fandoms and subjects I feel interested in. Even if I don't read my email, it still flows into the bubble and waits there for me to sift through it.
A mailing list is, essentially, topic driven. I want to read Legolas/Gimli fanfic and chat, I go to Axe and Bow. I want to discuss making vids, I go to Vidder. I don't post in those groups about the TV shows I watched on Monday night or what I did while I was waiting to read OotP. I stick with the mandate of the list.
I choose the topics, not the other people on the list. So you find quite a range of opinion, despite the fact that we're all interested in the same thing. Discussion can be quite lively, even flamy at times.
Mailing lists are about what you're interested in.
On LiveJournal, I am at the centre and everything revolves around me. My friends list is like a ring that encircles me. Every person I add makes the ring a little larger. Communities are another ring. The content falls from above and passes through me and my rings. It's transient, it's ephemeral.
LJ is people driven. It's true that I add people because of what they usually write about, but very few people stick to only one topic. So I read about what interests the people on my list, not about what only interests me. Sure, I skip right over those posts about the OC and Smallville. But I read about the movies they're watching and the other shows and sometimes I get whole new fandoms that way. I get opinions and thoughts that I wouldn't see on mailing lists.
But I also don't get all the posts on the subjects I'm interested in. I don't get all the HP fic or all the Stargate discussion. I don't think I'm really connected to LotR fandom on LJ at all. When the RotK trailer dropped, nobody was posting on my flist about it, so I went out to friendsfriends to see if I could find any commentary there. It's not very efficient. Fandom is, to me, what I'm reading.
It's also narcissistic. I post about whatever interests me, me, me! The Fandom of Hal's Brain. But everybody else gets to do the same. It's like when people first started putting up personal homepages. We all can shine like little stars in our own LJ solar systems, surrounded by a cloud of other people, connecting out to the edges of the known universe.
Discussion on LJ has a different tenor than on lists. Because I choose the people that you read, rather than the topics, I'm more likely to be of the same opinion as they are, and, when I'm not, I feel more of a desire to be conciliatory, out of a sense of personal connection. That's not to say that there's not dissension, but even that tends to have more of a personal tone.
LJ is about who you know.
Which Is Better
Eh. I think they're both great. Not like that sucky Usenet. *g*