Hello! How does Livejournal work? I don't quite understand it. Do you have individual profiles where you post your work and people go read it or...how do fandoms work on LJ? Thanks.
Each LJ account is a journal, just like each Tumblr account is a page of all of the stuff you’ve reblogged or posted. You could “friend” people, which made them show up in your “friends list”, which is like a Tumblr Dashboard.
Each account also automatically has a “profile” or “info” page. This is like the terribly underused profile pages on AO3 or like a Tumblr “about me” page or sidebar. The difference is that, on LJ, the page is always there whether you choose to do anything with it or not. In addition to whatever text the person has added about themselves, there’s also an “interests” section where you add site-wide tags. When somebody clicks on the tag for ‘slash’ or ‘meta’ or ‘vidding’ or whatever, they see a list of all of the accounts that have put that tag on their profile page.
Some people posted a lot of fic to their journals. I didn’t, and most of my f’list didn’t. More often, our posts were journal posts (how my day went, info about my new cat), meta about fandom, descriptions of whatever con or event we’d just been to, and that kind of thing. People also posted news: I found out about Yuletide that first year it ran from my whole f’list promoting it.
The big difference is that LJ posts cannot be reblogged. People respond in threaded comments discussions on the original post, which stays where it was originally posted, on that person’s LJ. Another difference is that tags on a specific post can only lead you to other posts on that same journal: If I’ve tagged my posts ‘meta’, and you’ve tagged posts in your own journal ‘meta’ also, there is no way to get a feed of both of those together. So, unlike Tumblr, if I want to tag all of my Poe stuff with ‘TFA’, those posts won’t get mixed in with The First Avenger or whatever else might use the abbreviation ‘TFA’.
LJ also has “friends lock”, so you can show different posts to different sets of people.
LJ communities are a different type of account: people with personal livejournals can post to a com, and it will show up in that com’s page but attributed to the original poster. Many fandom coms were mostly fic posts. Others might discuss canon or serve as newsletters linking to posts related to that fandom on other journals.
LJ’s features evolved over time. It eventually became easier to search for other fans and communities by interests and to search for posts by text they contained. The search got worse again in recent years after some Russian drama. But, overall, LJ was never very easy to search, and I never thought it was a good place to post fic. During the LJ years, I did a lot of my fic reading on archives: Fanfiction.net, Mediaminer.org, the old Yuletide archive (before it was imported to AO3), FictionAlley, Slash Cotillion, etc.
LJ did feature a lot of embedded art, but its native image hosting capabilities were a late addition. LJ fandom is much more about text than art/visuals. Some people are very happy about the move to Tumblr because their favorite thing is fan art, and that’s king on Tumblr. Other people miss the threaded discussions of LJ and don’t like how meta has all but disappeared on Tumblr.
Dreamwidth (DW) is similar to LJ. There have been other LJ clones that were important to fandom, like Insanejournal and Journalfen. Both LJ and DW are still somewhat active, though nothing like LJ was at its prime.
If you’re asking how fans found each other, most of my LJ friends are people who made interesting comments on the posts of other people I already knew. Some are people I found through communities for our shared fandoms. Some I found by looking at my friends info pages–which show who else you have friended–and checking out all of the journals listed. A lot were also people I knew prior to LJ from mailing lists and archives, and some were people I met in person at conventions or at school.