One is, of course, Wikipedia. Who'd have thought that a bunch of people could get together and build something that amazing. Criticised from the start; with calls of being hopeless, bound toward total inaccuracy, and an impossible goal; it has grown into the most complete and up-to-date repository of knowledge the world has ever seen. Excluding the obvious joke-entries that are bound to come up with such a system, it is on average likely to be the most accurate as well.
Another is Open Street Map. Who'd have thought that a bunch of people running around with their personal GPS devices could build the most comprehensive street-map that has ever existed. They did; over 160Gb of XML data, and counting. I say "over" because I don't want this article to be dated next week. Open Street Map now covers most of the developed nations on Earth, and a good part of the undeveloped ones too.
The third Web 2.0 project is something that most people don't think about, at least not in a positive way. It is the distributed data warehouse of content archived in the P2P networks. Most people think of piracy when the term P2P comes up, and they're right. The vast majority of content within the store is copyrighted and being used without permission. But, if you step back and look at it, the results really are stupendous.
Any casual browsing of torrent listings will show a staggering array of content. Basically, it contains pretty much everything that anyone has ever found interesting. Virtually every song, every application, every movie... TV shows, sporting events, scanned magazines and books, photos... the conglomeration of culture is astounding, and growing by the day. I wouldn't even hazard a guess at how many terabytes of data are available, searchable, and downloadable with a few mouse clicks. Any number offered would only be a guess, and even if accurate it would be obsolete within days. It is the single greatest aggregation of culture that humanity has ever created; the greatest libraries in the world are insignificant-nothings in comparison. In a day, a person could download more books that could be read in a lifetime, in a few weeks (only because data rates are often throttled by ISPs) more movies than could be watched in a lifetime, more applications than could be installed, more content that any human could ever consume. Not bad for a bunch of pirates.
Of course most of this content is there illegally, against the wishes of the rights-holders. But, how could this be any other way? There is no way such content could be legally collected, not without huge sums of money involved. For it to be done by people in their spare time, like Wikipedia and Open Street Map, it has to be free. Yes, the content isn't suppose to be free, but it will be.
Eventually, all the content in the P2P datastore will be legally free, either because the rights-holders have monetised those rights through a system like Keliso, or the copyright has expired. It won't be long before all new content will be released under pay-for-production systems, rather than the failed pay-for-consumption system we have now. Thus, eventually, it will all be legally free and waiting for us in the P2P datastore. Web 2.0 at its best. Who'd have thought a bunch of - insert your chosen expletive here - pirates could do such a thing.
What is Keliso?