Astral projection is the same activity as Lucid dreaming. The difference is that people whom believe in spirits, souls and ghost and other nonsense think of lucid dreaming as they are ''astral traveling''. It's the matter of understanding the philosophy of life.

And the shared dreaming is great. Of course you can't have other people's conciousness in your head, yet, with no cables... But you can summon your friend in a lucid dream and then you can speak about it with him in waking life. This is kind a possible fun of shared dreaming.