Your friend is right, grimmhammer. Up to eight people can play Minecraft online together at a time. I've never had that many people playing with me, though. Usually, it's just me and one or two other people.
I think it would be awesome to have 8 people playing Minecraft together, but I've never had that many people playing with me, either. The most I've ever had was four people, including myself. Most of the time, it's just me, though.
My friends who appreciate the Live feature are few and besides that, they all have busy lives. We only managed to play in 5, self included, and this was only one time. Oh well, it's still better than playing alone.
I've never gotten more than one other person to play online with me. I just don't have that many friends who are into Minecraft. My girlfriend likes to play, and one buddy that lives about an hour north. If neither of them will play, I'm stuck with playing solo.