I’ve already built a half-dozen groups on my Facebook profile (groups is a new feature that Facebook announced this morning). In my experience they are Twitter lists done right.

Twitter lists always had a lot of promise. Look at my lists. I have lists of venture capitalists. Lists of entrepreneurs. Lists of executives. Lists of journalists. Lists of pundits. Lists of companies. And more.

But over the last year since Twitter shipped its lists feature I’ve noticed a few problems.

1. Subscribing to, er, following, a list doesn’t do anything to your main feed.
2. A list can only have 500 members. One problem, I know about 800 executives already, and I’m discovering new ones every day. So, if, say, Steve Ballmer were to join Twitter and I wanted him on the list I’d have to remove someone already on the list.
3. I can have no more than 20 lists. I already have 20 lists, so if I were to keep a “executive A-F” list and another one for “G-Z” I’d have to put that on a new Twitter account. That doesn’t work.
4. No one can send a message to other people who are on the list. In fact, you might be on lots of lists and people could be talking to you but you’ll have no clue about that.
5. No way to DM or chat with other people on the list.

Now compare to Facebook’s new Groups.

First, listen to Mark Zuckerberg talk to me about the new features (Groups is one of three new features Facebook announced this morning — in the interview Zuck goes into depth about the groups feature after he talks about the other two features).

http://www.cinchcast.com/cinchplayerext.swf

But then consider just how much better Facebook’s groups are than Twitter’s lists.

They don’t have any of the above issues. That’s all great, but on Twitter there’s a power law that’s enforced.

Let’s say you are a hot new tech blogger, for instance. How can you get on my list? You can’t. I’ve filled up my list. So, until you convince me to kick someone else off, you won’t get on. That’s a power law that’s being enforced. Needlessly, too.

But even better, all my Facebook groups are now open to members to invite other people onto (the group founder has to change the settings to allow that). For instance, I have a Tech news and bloggers group. I didn’t invite half the people who are already on the list onto it. Zuckerberg explains how that’s controllable in our interview.

Everyone invited on can talk with each other. That’s very cool. Something that Twitter groups can’t do. That is an anti power law feature. Yeah, I, as administrator, can remove people, but generally I’m learning about some new people who friends of mine like. That is massively cool. I wish that could happen on Twitter. Or, at least, that I had a choice to make that happen on Twitter because there’s no way I can know every tech journalist/blogger in the world. Not to mention every VC, every executive, every pundit, every event manager, etc etc.

Now, take this into a smaller group setting. What about a family group? Well, I don’t know all of Maryam’s cousins who live in Tehran. So, if I had a Twitter list, it would be woefully incomplete. But on Facebook she can start a group and I can add to it. So can every member of it. That is massively cool, even for a family group. For an industry group, or a company group, that’s even more important.

Anyway, Facebook gets this social stuff at a level that most don’t. Listen to how Zuckerberg talks about the experience of me adding him to a group. It’s a nuanced view and one that goes way beyond what I hear from Twitter and Google. Apple? They have no clue. Nokia and Microsoft? No clue either.

Why is Zuck king of the social world? Well, start a group and we’ll talk about it!