"Open" is a great thing. Everyone likes it. Unfortunately, nobody agrees what open is. There are many meanings, but in general, I think "open" must be the opposite of "closed". In the world of abstract things like software, protocols and society, closed is secret, hidden, or locked.
"Closed" limits our mobility, prevents discovery, and discourages new connections. Imagine being in a building where all of the doors are locked or guarded, and it's difficult to move from room to room or leave. A closed world is one where people are forced to stay in their place, sometimes because of physical constraints, but more commonly because they simply don't know where else to go. A closed world is giant prison.
In an open world, people are able to see more clearly, and more easily explore new ideas and possibilities. An open world is more fluid -- people and ideas easily flow over boundaries and other borders. This openness is what makes the Internet so powerful. The Internet is melting the world, but in a good way.
Open standards and open source software are important for making technology open and available to everyone, but it's important to remember that open goes beyond tech. Wikipedia makes knowledge open to everyone. Blogs and YouTube make broadcasting and mass communication open to everyone -- news and events that would have been suppressed in the past are now reaching the whole world.
These things have been discussed to death, but there's another "open" that still seems a little frivolous: our lives. We like to joke (or complain) about people who share every boring detail of their lives and thoughts on Facebook or Twitter, but they may be doing something important.
Most of our happiness and productivity comes from the everyday details of our lives: the people we live and work with, the books we read, the hikes we take, the parties we attend, etc. But how do we choose these things? How do we know what to do, and how do know if we'll like it? The obvious answer is that we do and like whatever the TV tells us to do and like. I'm not certain that's the best answer though.
By sharing more of our own thoughts and lives with the world, we contribute to the global pool of "how to live", and over time we also get contributions back from the world. Think of it as "open source living". This has certainly been my experience with my blog and FriendFeed. Not only do people occasionally say that it has helped them, but I've also met interesting new people and gotten a lot of good leads on new ideas. These are typically small things, but our lives are woven from the small details of everyday living. For example, I saw a good TED talk on "The science of motivation", shared it on FriendFeed, and in the comments Laura Norvig suggested a book called Unconditional Parenting, which turns out to be very good.
The next step is for people to open more of their current activities and plans. This is often referred to as "real-time", but since real-time is also a technical term, we often focus too much on the technical aspect of it. The "real-time" that matters is the human part -- what I'm doing and thinking right now, and my ability to communicate that to the world, right now. We see some of this on Facebook, FriendFeed, and Twitter, and also location-aware apps such as Foursquare, but it's still fairly primitive and fringe. When this activity reaches critical mass, it should be very interesting for society. It dramatically alters the time and growth coefficients in group formation. It enables a much higher degree of serendipity and ad hoc socializing.
The basic pattern of openness is that better access to information and better systems lead to better decisions and better living. This general principal is broadly accepted, but we're just now discovering that it also applies to the minutiae of our lives.
Sharing your boring thoughts and activities may seem narcissistic and self-absorbed at first (I'm still kind of embarrassed about having a blog), but there is virtue and benefit in it. Naturally there will be challenges and fear along the way, but in the long term we're contributing to a more open, fluid society, where people are more able to find happy, productive lives. It also encourages us to be more accepting of others. Everyone is flawed, and the more we see that we aren't alone, the less we need to fear that truth.
People can not truly live and thrive in a prison -- we require freedom and mobility. This may explain my incomprehensible analogy, "Open as in water, the fluid necessary for life".
Go forth and share.