I never do these Writer's Block questions. Heaven knows, I don't have writer's block when it comes to LJ -- I have to work hard to not post multiple times a day. However, this is a question I'd like to answer.
My first impulse was to be flippant. "I love how stable it is, the lack of downtime, the outstanding customer support!". I got over that fast though.
I love LJ. I love how it lets me stay in contact with people. All the FFXI people who I would have long since no longer been able to talk to. Fandom people. PokeMUSH
My journal was created on August 15, 2002. I've written 4,811 entries. But the most important stat? 39,636 comments received, 39,803 comments posted. That's what I love about LJ -- the interactions. The conversations. Conversations about the most important things in life, conversations about the silliest things (who wants a cute kitten video!).
LiveJournal is a big part of my life. Even just the act of writing posts often helps me feel better (and if worse comes to worst and it's too sad/negative to post, there's the 'private' setting so no one will see it but me).
In the last few weeks, I've had an influx of IC (in character/fictional) journals onto my friends list, which is just another dimension of enjoyment.
I may be the biggest introvert on the planet in RL, but through LJ I can meet new people and interact with anyone in a safe, comfortable way. Thank you, all of you on my friends list and anyone else who happens to know of my journal, for making my online life all the better. Thank you to LiveJournal as well.