The other "community" is, "livejournal.livejournal.com." It keeps you updated about LJ - but most of it is in Russian! Still, it might be worth adding. Check out what it is watching - a bunch of new, official LJ communities or something - which appears to be a recent development, but which hasn't gone too far yet.
I don't know where to look to find LJ's top 15. When I look in the first community above, there are just way too many posts to dig through. Do you know where these can easilly be found? Well, I think one of my posts hit top 15 - although I don't know what the qualifications are. Then, all these Russians started reading my journal.
Or - maybe that was just because I made a comment in a popular journal, which normally doesn't allow comments to get through. It is a good journal to add, for the little news exposes it does. leonkuravson. It's some guy who says he is in WDC, but who knows it might be Putin, yars.
I added a bunch more LJ live feeds to my flist - and it swamped all of you - completely burying you all. But, they are great feeds. So, I have been digging myself out, by transferring them over to "commie_gardener". If you want to keep another tab on science, news, etc., then you can tag commie_gardener's flist in your browser, and watch these feeds roll by, when you're having a rainy day! Go here: http://commie-gardener.livejournal.com/friends. (If you add him, you can request not to be added back).
I have a bunch of my own communities. I'll post a note about my most active ones soon. Most others are moribund. But, you can see more about them in communities101. You are all invited to add that community. The theory is that it will keep you updated about other communities.
And, then of course, there's this: Add your name to my map! You can also check your interests there, so I can include you in custom groups/filters, or exclude you, to perpetual blandness, amen.