Among Web 2.0’s key attributes are the growth of social networks, bi-directional communication, diverse content types, and various “glue” technologies, and the authors note that while most of Web 2.0 shares the same substrate as Web 1.0, there are some significant differences. Features typical of Web 2.0 Web sites include users as first class entities in the system, with prominent profile pages; the ability to connect with users through links to other users who are “friends,” membership in various types of “groups,” and subscriptions or RSS feeds of “updates” from other users; the ability to post content in various media, including blogs, photos, videos, ratings, and tags; and more technical features, such as embedding of various rich content types, communication with other users through internal email or instant messaging systems, and a public API to permit third-party augmentations and mash-ups. Web 1.0 metrics of similar interest in Web 2.0 include the general portion of Internet traffic, numbers of users and servers, and portion of various protocols. About 500 million users reside in a few tens of social networks with the top few responsible for the bulk of the users and traffic, and traffic within a Web 2.0 site is more difficult to measure without help from the site itself. The challenges for streamlining popular sites for mobile users differ slightly between Web 1.0 and Web 2.0, in that instant notification to users through mobile devices can be facilitated because of the short or episodic nature of most Web 2.0 communications. Most communication in Web 2.0 is between users, so Web 2.0 sites have no easy way to select during overload; however, the sites apply varying restrictions to guarantee that overall load and latency is reasonably maintained. Some of the Web 2.0 sites are eager to maximize and retain members within an “electronic fence,” which can facilitate balkanization, although total balkanization is likely to be prevented by a countercurrent stemming from the prevalent link-based nature of Web users continuously connecting to sites outside the fence. The authors point out that there are substantial challenges in permitting users to comprehend privacy implications and to simply represent usage policies for their personal data.
First Monday (06/08) Vol. 13, No. 6, Cormode, Graham; Krishnamurthy, Balachander