Web 2.0 is a buzzword taken to mean many things, but generally it is about democratising media. It is about user-generated content, but also relying on user input through the 'wisdom of crowds' to rank, tag, sort and organise that content. Some examples: Google The world's most-popular search engine is Web 2.0 because it incorporates democratic elements into its search algorithm, treating links to a site as a 'vote' for that the site. This produces highly relevant and accurate search results. To see this democracy at work, Google the word 'failure' and the top result is the biography of US President George W. Bush. The practice, known as Google bombing, occurs because bloggers have used the phrase 'failure' to describe and link to Mr Bush's biography. YouTube The popular video-sharing site (and many others, such as Revver, Vimeo, Veoh and Video Egg) offers a platform where users can upload their videos to be seen by others. The very best clips are spread virally via links, blogs or e-mails to friends. Other features such as 'highest ranked', 'most viewed' and 'most commented on' also help separate the wheat from the chaff. The video-sharing sites can trace their lineage to Flickr and other photo sites. Digg.com Digg is a news site that does not produce any news of its own. Users submit links to news stories along with a short description, and those stories go into a general pool to be 'dug' by the community. Stories receiving a lot of 'digs' go to the front page. The non-hierarchal process takes control away from editors and places it in the hands of the readers, who decide which stories are important. Similar sites include Reddit.com and Fark.com. Wikipedia The online encyclopedia has more than 6 million articles across 171 languages. Any of Wikipedia's millions of users can contribute or edit an article, leading to highly detailed entries through the 'wisdom of crowds' effect, but sometimes vandalism or inaccuracy. However, articles are often quickly repaired once brought to the attention of the Wikipedia community. A study by scientific journal Nature found sections of Wikipedia to be close to its print counterpart, Encyclopedia Britannica, in terms of accuracy on articles concerning natural sciences. Technorati This blog search-engine keeps track of the buzz on more than 60 million blogs. As this is being written, Technorati can tell visitors that James Brown is the most-recent popular search query, while an article on the detention of Iranian officials in Iraq is the most-linked-to-news item. Similar features that mine user search data and activity have been incorporated into sites such as Yahoo.