An interesting LJ observation

[hrj]

So every once in a while I browse some of my LJ-friends friends-lists to see who else might be posting interesting things that I'm not reading regularly. What I find is that even for people with whom I share only about 20% of our friends-lists, the overlap in content of our friends-postings is typically around 60-80%. Part of this is that -- because I f-lock so few of my posts -- I don't feel the need to friend people just so they can read me. So if I get friended and on poking around I discover that the person either doesn't post much of anything or only posts memes, I generally don't friend back. So if I'm comparing f-lists with someone and they don't have a similar strategy, our f-list overlap percentage is going to be smaller than otherwise. It's also possible that a fairly high proportion of posters (overall) f-lock their posts and, of course, when I browse someone else's f-list I only see postings from people we have in common or who don't f-lock. Checking my own f-list postings, if I eliminate feeds and communities, about a third of the posts I see are f-locked. So someone else viewing my f-list would only see 2/3 of the personal postings that I see. If my friends and my friends' friends f-lock at similar rates, then if I share 20% membership with someone, and I see 100% of the 20% overlap posting but only 67% of the 80% non-overlap posting, then I'd expect the shared visible postings to be 20/(20+54)= 27% overlap of what I see on that persons f-list. Now to approximate the effects of my not friending non-posters (and thus artificially decreasing the potential f-list overlap) I note that people I haven't reciprocally friended represent about a quarter of the number of mutual friends I have. But as a wild-assed estimate, if this increased the potential f-list overlap to 25% (from 20%), then the expected shared visible postings would be 25/(25+50)=33%, and still not close to the approximately 60% or so overlap that seems to be the minimum I see.

From this, I jump to the completely unwarranted conclusion that my friends are simply, on average, much more interesting and prolifically-posting people than other people's friends. :)