The older readers will probably remember Napster back in the early days when it was one of those "pirate services." It was a place you could go to share music with other users and get music for free.
But it was shut down in 2001 by a court order during a legal battle with the infamous RIAA. In spite of the legal uses of Napster, such as small bands purposefully sharing their music on Napster to gain notoriety, the court issued an injunction preventing Napster from continuing its service.
The thing which made this "shut down" possible was the fact that Napster was run in a top-down manner. All of the workings involved in the process of sharing were housed, funded, and maintained centrally.
As we all know, users found other ways of sharing files. The first such method of note was several p2p services such as Kazaa. Then came the revolutionary BitTorrent protocol. These have the advantage that the workings are not under centralized management. The way these pieces of software work, everybody distributes, so to shut it down, everybody has to be dragged into court, and that's just not practical.
Today, there is another centralized system in danger of being curtailed which has a much greater impact on Internet users' freedoms.
The Internet began in the United States and the United States continues to exert draconian control over it. Many of you probably know that the United States congress currently threatens to put through SOPA, a bill which would allow unprecedented curtailing of the DNS system for corporate interests.
But, there are efforts underway to make a decentralized systems for communication not so susceptible to censorship. Here are a couple.
The B.A.T.M.A.N. Protocol
The B.A.T.M.A.N. (Better Approach To Mobile Ad-hoc Networking) protocol, aside from having an awesome acronym, is a p2p network protocol not (necessarily) dependent on lower-level network protocols suitable for large, self-organizing networks. It may be used on most devices which support the Wifi protocol and could one day replace the internet.
The general use case for this protocol is to install custom firmware (such as DD-Wrt or OpenWrt) on wireless routers and make these wireless routers act as B.A.T.M.A.N. nodes which may automatically connect to each other, creating a large-scale, self-organizing, wireless network which end-user devices (such as computers) may connect to in order to communicate with each other. The B.A.T.M.A.N. protocol may also be tunneled, allowing for communications over the Internet or over other network protocols for situations where it is not feasible to communicate via the normal low-power radio frequencies used by normal wireless cards.
One day, each city may have its own city-wide B.A.T.M.A.N. network. These networks might be connected to other city B.A.T.M.A.N. networks via ham radio band communications, phone networks, cables, or any number of other methods.
Project meshnet is an active grassroots attempt to engineer a way to create a mesh network with the ability to replace the Internet. Much of their planning is done on Reddit. They're still in the early planning stages, but they appear to be very serious about the effort and have a lot of expertise among them.
They may eventually decide to use the B.A.T.M.A.N. protocol or not, depending on what decisions are made about the needs of the user. B.A.T.M.A.N. is definitely a good contender, however.
If you'd like to help out the project, go to projectmeshnet.org and sign up to their forums. Being active on their subreddit is also recommended.
The less we have to depend on service providers, the less governments and corporations may interfere with our rights to free speech.