Web 2.0 involves interactive websites that facilitate sharing and collaboration. It evolved from static websites (Web 1.0) with the rise of social media, user reviews, wikis, and other sites where people interact and contribute content. Key aspects of Web 2.0 include long-tail content, ubiquity via internet access, network effects, and near-zero marginal costs of content production and sharing. Examples given are Wikipedia and other collaborative sites versus traditional top-down encyclopedias and search engines. Mass collaboration is seen as a strength, as with Wikipedia's open editing model. Companies like Google harness participation via mechanisms like PageRank, AdSense, and facilitating content sharing. The boundaries between companies and participants blur as value