Social networking
Social networking sites enabled probably the greatest migration of people to the virtual world. People have a new opportunity to interact not only in real life, but also in cyberspace, where geographical and other physical barriers don't exists. I'm not saying this is a promising thing overall, some people are obviously overdoing it, but it's still useful for keeping in touch with people. Together with the implementation of feeds and streams which enable dynamic information, social networking could represent the biggest and most important component of Web 2.0, reshaping business, marketing, politics and just being plain amazing.
Video sharing
Yesterday we read the newspaper, listened to the radio and watched television. Today, we have a super-medium that supports all of it at once. Video, as the most complex form of multimedia, is something that you can record with your telephone and publish online in minutes, from where it can go anywhere. If distributing a video is easy, anything else surely has to be a piece of cake. This fact obviously holds massive potential for science and arts in general.
Wikis and folksonomies
Wikis and folksonomies are tools which harness the amazing effect of participation and collaboration of millions of people to create information and knowledge. Wikipedia is the biggest encyclopedia in the world, holding knowledge whole mankind can benefit from. Folksonomies, such as tools for collaborative tagging and social indexing enable structured knowledge, while recommendation engines help us get information from massive quantity of data available online. Today, if something important is discovered, everybody knows it in minutes.
Blogs
Most people have the need to express themselves, and blogs (and microblogs) are the perfect tool for that. Plain and simple: anybody can be a journalist and if you have something smart to say, people will listen. Those who are influential enough can even break out of anonymity and become opinion leaders.
Web services and mashups
Web services and mashups enable and use open flows of data from one online service to another, from one online platform to another. System integration used to be one of the most complex things in IT, but thanks to new standards, protocols and technology, data can freely travel from and to different sources. This provides a perfect ground for exchanging information and enables evolution from software services to software platforms.
Perhaps we should also mention cloud computing, which makes hardware requirements irrelevant – the processing power and memory is around in plenty – but computer grids with shared resources have already been around for decades. All the better to understand that Web 2.0 is more about concept than it is about technology.
Web 2.0 is important and revolutionary, both in a good and a bad way. It brings a new perspective and new opportunities to different arts and sciences, such as business, education, sociology, psychology, literature, politics and many other. My professional and academic work focuses mainly on it's influence on information science and technologies, but it's clear that this new paradigm has a huge global effect, whose scale we still can't fully estimate. Now we just have to hope younger generations don't get too overwhelmed because of it and will be able to adjust to this new reality without abusing it too much.