The latest Beta lets you right-click on any item in the Places window and “Share with Google Earth Community…” So what does that mean?
What it does do is offer a shortcut to posting network links, layers or placemarks to a forum on Google’s own Google Earth Community bulletin board. This makes the process just a little bit quicker than saving the item and then going to a forum there to post it.
What it doesn’t do is let you store the contents of your Places window online, so that other people can subscribe to them, live. That kind of sharing is still a little ways off, presumably.