- In LJ you get a good sense for the day-to-day life of your friends (assuming people post about that) and it's captured for eternity (until it's deleted), so you can refer back to it.
- In SL you build friendships by doing things together (dancing, hiking, scuba diving, having coffee together) and chatting. Once you get closer to someone, you begin to hear about their first life. You know when you hang out a good friend and you talk for hours and lose track of time? That happens a lot in SL
- In LJ you can readily see who someone's community is through the others' comments--in SL you only meet your friend's friends if you run into them when you're out together..or if your friend chooses to introduce you. Or unless your friend joins one of the many SL blogs and you see friends there.
- Both LJ and SL have "groups" based on interests and profiles where people can define themselves, in words and photos. In LJ you post in these--in SL they are used to announce shared activities--often in real time. In LJ community is built through the community posts
- Lonely? In LJ: Log on, read over posts, comment..or post. In SL: log on..see which of your friends are on & chat or do things together---No one on? then search for group events that are happening now and go and meet some new people. Depending on what time of day it is you'll be more likely to meet people from different parts of the world.
- Expressing creativity: In LJ you'll see wonderful writing, poetry, photos, videos. In SL: people most often express their creativity through making things--clothes, art, gardens, buildings. However, musicians play their music, there are live poetry readings, video feeds, and art shows/openings galore (in the art world, the artists often create the context within which to display their art).
I'm sure I'm missing some elements here...feel free to add some. Of course, I've phrased this as a contrast, but the reality is that the two worlds overlap a great deal--many of the new developments in SL are the interfaces between SL and the Web (RSS feeds, email clients in SL, etc.).
Cross posted in my first life journal as well.