Danny Ayers had his most recent column at IEEE Internet Computing: Evolving the Link. In this article, Ayers summarized his vision of how web links evolve with the progress of World Wide Web. Agreeing with his vision, I, however, have some supplementary thoughts about the evolution of web links.
Before presenting my supplementary thoughts, I would like to briefly review what Danny presented about web link evolution. In general, Danny's vision followed a strict technical line. At the beginning, web link were anonymous connections that linked one web page to another. Using his example, "< href="http://creativecommons.org/licences/by/2.0/">cc by 2.0< /a>" produces an anonymous connection from the page that contains this specification to a particular web location: "http://creativecommons.org/licences/by/2.0/". Though each destination has its distinctive meaning, web links themselves mean nothing else except that the referenced web resources are ABOUT the local text. The meaning of ABOUT is, however, simply too rich to be properly distinguished.
To solve the problem, the "rel" attribute is designed so that it describes de relationship from the current document to the destination resource. For example, "< href="http://creativecommons.org/licences/by/2.0/" rel="license">cc by 2.0< /a>" shows the meaning of the link to be "license." Again, this solution still has its problem because the meaning of content inside the rel attribute is often not machine-processable.
In this column article, Danny presented that a potential solution to this last problem is to treat links as data. Thus, we map not only data but also links to proper RDF descriptions. With these mappings, machines can automatically interpret the meanings of not only resource nodes on the web, but also the links among these resource nodes. This vision of web links thus concluded the article.
Nevertheless I agree with Danny's vision, I feel something else also important to the evolution of web links but missed in discussion at this article. Besides semantic meanings, vulnerability is another essential aspect of web links. Traditionally handcrafted, anonymous web links are often vulnerable to individual prejudice. For example, I have produced a normal web link from this post to Danny's blog, which shows a relation of this post to Danny. Meanwhile, I can also subjectively remove this link (but not the content) so that there becomes no immediate link from this post to Danny, though indeed there should be such a link since the content is not changed. This simple example shows a basic problem about traditional links---they are vulnerable to individual prejudice.
Though to solve this vulnerability problem is not the intentional driving force of web link evolution, an important side effect of this evolution is the gradual invulnerability of web links. With the emergence of Web 2.0, more and more indirect web links are created based on common tags. For example, I have tagged this post with a keyword "Danny Ayers," while at the same time, Danny's blog is also tagged by the keyword "Danny Ayers." Therefore, even if I have removed a normal href-style direct web link in my post to Danny's blog, there is still an immediate link between this post to Danny's blog because we have shared a common tag. Due to the objectiveness of tagging, this type of web links becomes less vulnerable to individual prejudice than the previous purely handcrafted web links.
When the web evolve forward to the ideal semantic web, we can predict the creation of more and more objective links between web resources. These links are going to more and more based on common meanings (objectiveness) rather than individual preferences (subjectiveness). As Danny presented in his column, when links are shared as open data annotated by formal taxonomies, the existence of these links becomes less and less vulnerable to individual prejudice. It is the content itself that would decided the links.
This evolutionary aspect of web links is important to not only web links, but also the WWW in general. It means that the web is going to be weaved not only in more and more details, but also more and more objectively. Based on this conclusion, we can make several interesting predictions about the future web.
- Tags and annotations are going to be premier resources on web search. Due to their objectiveness (less vulnerable), the network composed by tags and annotations is going to be more stable than the network composed by handcrafted links. This fact may significantly help improve the efficiency of web search.
- The weight of tags and annotations are going to be more and more critical on ranking research results. The balance between these weights (the side of objectiveness) and link popularities (the side of subjectiveness) will be an essential issue on new web search ranking algorithms. Does it mean the dusk of the PageRank algorithm and thus the declining of Google? We are not sure yet. But at least this is not a positive news to Google.
- Tags and annotations are going to weave the web into close-related communities with distinct topics. As a result, vertical search engines may replace horizontal search engines becoming the basis of web search. At present, vertical search is relied on horizontal search and then provide more details on particular domains. In the future, horizontal search will be based on vertical search and then provide more details on cross-domain communication. This role switch on web search may significantly affect the structure of web industry, especially the web search businesses.
I have more discussions on web evolution in general in my article of Evolution of World Wide Web. The most recent post is the Part 2, Web Evolution Theory and The Next Stage. In this part, we studied several web evolution laws and composed them together to be a basis for predicting the evolutionary future of World Wide Web. Though these are only our viewpoints, we hope it brings some fresh air into the study of web evolution.