Immense user effort realized the potential of each of these technologies. The difference with Web 2.0 is actually not you, or me, or the rest of the world. The difference is the tools. It's not the fact that everyone is creating so much more content (though they are) it's that the newest tools have enabled the distributed creation of high quality content. Digg's view of the web is far more than the sum of its votes. The network effects of social networking services are more directly visible and usable than more significant and plentiful user-initiated connections on the unstructured web, and that makes them more useful in their specific context.
Internet technologies represent the cutting edge of how we as a civilization build things. From non-mechanical tools we fashioned mechanical devices. The mechanical gave rise to the electrical, the electrical to the electronic, and with the advent of computers, the "machines" transcended physical limitations. With software, the exact same physical machinery could be used to build and operate an unlimited set of applications. We could build virtual skyscrapers in the sky, tear them down, and rebuild them, over and over again. Computer networking, and eventually the Internet, allowed that same software to be distributed at zero marginal cost, further increasing its power, flexibility, and usefulness. The web then gave us direct access to a virtually infinite number of software applications and allowed us to leverage far more computing power than any of us could individually afford.
Now, with Web 2.0 technologies, we have established meaningful modes of interaction, including both data and social protocols, to allow non-engineers to collectively contribute to the creation of the newest virtual tools and mechanisms. And that is a remarkable achievement, the credit for which goes to the creators of those systems (and sorry, not me, you, and everyone else). But I can see how picking 50 entrepreneurs wouldn't work, as well as why Web 2.0 itself couldn't be POTY. Although "The Computer" was chosen in 1982, I don't think Time or its readers are ready to choose a category of software applications as the most influential "thing" of the year. Still, even the recognition of these technologies through its users is a striking choice, one which will hopefully further catalyze innovation in this area.