Communities are 3/4 the way there; a little more work tomorrow and the basics will be in place. Currently you cannot create your own community, but feel free to join Elgg Features by clicking the button next to the community name, just as you would add someone to your friends list. The button for communities will change eventually.
Once you’ve joined you’ll find you can post to the community weblog and upload to the file repository. All community postings will also show up on your friends page.
Remember, this is very much in testing still; tomorrow once I know it’s stable I’ll make an announcement in the news weblog.