Hyperlinking is the foundation of the web As users add new content, and new sites, it is bound in to the structure of the web by other users discovering the content and linking to it. Much as synapses form in the brain, with associations becoming stronger through repetition or intensity the connections grows organically as an output of the collective activity of all web users Yahool, the first great internet success story, was born as a catalog, or directory of links, an aggregation of the best work of thousands, then millions of web users. While Yahoo! has since moved nto the business of creating many types of content, its role as a portal to the collective work of the net's users remains the core of its value Google's breakthrough in search, which quickly made it the undisputed search market leader, was PageRank, a method of using the link structure of the web rather than just the characteristics of Bay s product is the collective activity of all its users; like the web itself, e Bay grows organically in ny's activity can happen. What's more, eBay,s competitive advantage comes almost entirely from the critical mass of buyers and sellers, which makes any new entrant offering similar services significantly less attractive. Amazon sells the same products as competitors such as Barnesandnoble. com, and they receive the same product descriptions, cover images, and editorial content from their vendors. But Amazon has nade a science of user engagement. They have an order of magnitude more user reviews, invitations to participate in varied ways on virtually every page--and even more importantly they use user activity to produce better search results. While a Barnesandnoble. com search is likely to lead with the companys own products, or sponsored results, Amazon always leads with"most popular real-time computation based not only on sales but other factors that Amazon insiders call the"flow around products. With an order of magnitude more user participation, it's no surprise that Amazons ales also outpace competitors. Now, innovative companies that pick up on this insight and perhaps extend it even further, are making their mark on the web Wikipedia, an online encyclopedia based on the unlikely notion that an entry can be added by any web user,and edited by any other, is a radical experiment in trust, applying Eric Raymonds dictum (originally coined in the context of open source software) that with enough eyeballs, all bugs a shallow, to content creation. wikipedia is already in the top 100 websites, and many think it will be in the top ten before long. This is a profound change in the dynamics of content creation Sites like del icio. us and Flickr, two companies that have received a great deal of attention of late, have pioneered a concept that some people call"folksonomy"(in contrast to taxonomy), a style of Elaborative categorization of sites using freely chosen keywords, often referred to as tags. Tagging allows for the kind of multiple, overlapping associations that the brain itself uses, rather than rigid categories. In the canonical example, a Flickr photo of a puppy might be tagged both"puppy"and cute"--allowing for retrieval along natural axes generated user activity Collaborative spam filtering products like Cloudmark aggregate the individual decisions of email user about what is and is not spam, outperforming systems that rely on analysis of the message It is a truism that the greatest internet success stories don't advertise their products. Their ado ption is driven by viral marketing"--that is, recommendations propagating directly from one user to• Hyperlinking is the foundation of the web. As users add new content, and new sites, it is bound in to the structure of the web by other users discovering the content and linking to it. Much as synapses form in the brain, with associations becoming stronger through repetition or intensity, the web of connections grows organically as an output of the collective activity of all web users. • Yahoo!, the first great internet success story, was born as a catalog, or directory of links, an aggregation of the best work of thousands, then millions of web users. While Yahoo! has since moved into the business of creating many types of content, its role as a portal to the collective work of the net's users remains the core of its value. • Google's breakthrough in search, which quickly made it the undisputed search market leader, was PageRank, a method of using the link structure of the web rather than just the characteristics of documents to provide better search results. • eBay's product is the collective activity of all its users; like the web itself, eBay grows organically in response to user activity, and the company's role is as an enabler of a context in which that user activity can happen. What's more, eBay's competitive advantage comes almost entirely from the critical mass of buyers and sellers, which makes any new entrant offering similar services significantly less attractive. • Amazon sells the same products as competitors such as Barnesandnoble.com, and they receive the same product descriptions, cover images, and editorial content from their vendors. But Amazon has made a science of user engagement. They have an order of magnitude more user reviews, invitations to participate in varied ways on virtually every page--and even more importantly, they use user activity to produce better search results. While a Barnesandnoble.com search is likely to lead with the company's own products, or sponsored results, Amazon always leads with "most popular", a real-time computation based not only on sales but other factors that Amazon insiders call the "flow" around products. With an order of magnitude more user participation, it's no surprise that Amazon's sales also outpace competitors. Now, innovative companies that pick up on this insight and perhaps extend it even further, are making their mark on the web: • Wikipedia, an online encyclopedia based on the unlikely notion that an entry can be added by any web user, and edited by any other, is a radical experiment in trust, applying Eric Raymond's dictum (originally coined in the context of open source software) that "with enough eyeballs, all bugs are shallow," to content creation. Wikipedia is already in the top 100 websites, and many think it will be in the top ten before long. This is a profound change in the dynamics of content creation! • Sites like del.icio.us and Flickr, two companies that have received a great deal of attention of late, have pioneered a concept that some people call "folksonomy" (in contrast to taxonomy), a style of collaborative categorization of sites using freely chosen keywords, often referred to as tags. Tagging allows for the kind of multiple, overlapping associations that the brain itself uses, rather than rigid categories. In the canonical example, a Flickr photo of a puppy might be tagged both "puppy" and "cute"--allowing for retrieval along natural axes generated user activity. • Collaborative spam filtering products like Cloudmark aggregate the individual decisions of email users about what is and is not spam, outperforming systems that rely on analysis of the messages themselves. • It is a truism that the greatest internet success stories don't advertise their products. Their adoption is driven by "viral marketing"--that is, recommendations propagating directly from one user to