What Is The Web?
October 27, 2008
This question doesn’t usually matter very much, but sometimes we get into arguments about whether something (eg e-mail, streaming video, instant-messaging) is part of “The Web” or not.
Due to various circumstance last week I found myself drafting this text about it (while kicking myself and telling myself it was a waste of time). Jet-Lag Insomnia, more or less.
I think the main value of my text, or any effort like this, is in revealing our often-unstated ideas about what the Web can or should become. Is this “architecture”? When you renovate a building, adding new wings, how much are you changing its architecture? How much are you changing its subtle good and bad features? Certainly it’s good to think about that question before making the changes.
It is also nice to get our terms straight. I loathe the term “Resource” and quite dislike the term “URI”. Along the way here, I try to define what I think are the key terms in Web Architecture. For extra credtit, I end up with defining a “Web Standard”.
Wikipedia says the Web is:
…a system of interlinked hypertext documents accessed via the Internet.
In contrast, WebArch says it is:
…an information space in which the items of interest, referred to as resources, are identified by global identifiers called Uniform Resource Identifiers (URI)
Without going into my dislike for WebArch, I really wish the Semantic Web would/could (somehow) stick to a definition closer to Wikipedia’s.
My one-line defintion is this:
The Web is a global communications medium provided by a decentralized computer system.
In more detail:
“The Web is a global…”: Although conceptually there could be many different “webs”, there is one which is understood as “The Web”. The Web follows (and uses) The Internet in being designed to connect different local systems. An installation of web technology usually ends up connected to others, becoming part of the unified global Web, because in most situations the value of doing so greatly outweighs the costs. The end effect is a single, integrated system built up of all available, connected components.
“communications medium” : The Web provides a way for people to communicate with each other. It does this by letting them create web pages (often collected into web sites), with unique names (the web address, or URL), which other people can view and interact with. The system does not restrict what exactly constitutes a “page” (sometimes called a “resource): originally, Web pages were essentially an on-line of paper documents, but they have evolved to now provide, within each “page”, a full user interface to remote computer systems. The web addresses are essential, because they allow people to communicate about particular pages and, crucially, they allow one page to name another (to link to another) so that user can learn about and “visit” (use) other pages.
Although generally intended for use by people, the Web is sometimes used by other computer systems. A search engine traverses the Web like a user, and then helps users find the pages they want. The Web Services and Semantic Web standards provide various ways for computer systems to interact with each other over the Web, attempting to leverage Web infrastructure as an element in new systems.
“decentralized computer system”: While the Web is in one sense a single system, it is composed of other computer systems, most of which serve as web servers or web clients. It has no central point of control (except perhaps the Domain Name System (DNS), which is part of the underlying Internet); instead, the system’s behavior for a particular user depends on the clients and servers being used by that user. Many features of the Web rely the behavior being essentially the same for all users, and that consistency depends on the underlying systems behaving consistently. Where there is consistent behavior, and that behavior is documented, the document is a Web Standard.