Never the Same Stream: netomat, XLink, and Metaphors of Web Documents Colin Post Patrick Golden Ryan Shaw University of North Carolina at University of North Carolina at University of North Carolina at Chapel Hill Chapel Hill Chapel Hill School of Information and School of Information and School of Information and Library Science Library Science Library Science [email protected] [email protected] [email protected] ABSTRACT value for designers and engineers of studying “paths not taken” during the history of the technologies we work on today. Document engineering employs practices of modeling and representation that ultimately rely on metaphors. Choices KEYWORDS among possible metaphors, however, often receive less Hypertext; XLink; browsers; XML; digital art attention than choices driven by practical requirements such as performance or usability. Contemporary debates over how to meet practical requirements always presume some shared 1 Introduction metaphors, making them hard to discern from the surrounding context in which the engineering tasks take place. One way to The metaphor of the printed page has been a prominent address this issue is by taking a historical perspective. In this and indeed from the earliest implementations of hypertext. paper, we attend to metaphorical choices by comparing two structuring principle of Web documentsd hypertext since in the contrast �irst browser, to the historical case studies of “failed” designs for hypertext on the printed page, as whatever “could not conveniently be netomat (1999), a Web browser created preAlthoughsented Nelsonor represented �irst de�ine on paper” [29, page 96], many by the artist Maciej Wisniewski, which responded to search subsequent hypertext systems treated documents as queriesWeb. The by �irst generating case is dynamic streams of text, image, and metaphorical pages (or cards, which we might think of as small audio culled from across the Web and structured by a custom pages). Although web browser interfaces still refer to markup language. The second is the XML Linking Language documents as pages, there is a more complex relationship (XLink), a W3C standard to express hypertext links within and between the metaphors used to make sense of reading and writing hypertext and Web document structure. This between XML documents. XLink and netomat, both developed relationship between metaphor and structure has varied over in the late 1990s, were motivated by concerns about the the history of the Web, and at different points in time, minimal linking model implemented in contemporaneous alternative its HTML standards and Web browsers. Our analysis focuses on ongoing development. the relationship between the metaphors used to make sense of Wemetaphors provide historical and structures case studies have of two in�luenced such efforts Web documents and the hypermedia structures they compose. to explore other metaphors and structures for Web documents. The metaphors offered by netomat and XLink stand as One case is netomat (1999), both an artwork and functional alternatives to metaphors of the “page” or the “app.” Our intent browser developed by Maciej Wisniewski that structured here is not to argue that any of these metaphors are superior in documents according to the metaphor of the stream, pulling some transcendent way. Instead we consider how designers’ text, image, and audio from across the Web, and juxtaposing and engineers’ metaphorical choices are situated within a The other case is the XML Linking Language (XLink), a W3C complex of already existing factors shaping Web technology standardthis heterogeneous to express content hypertext into links a dynamic, within �lowingand between document. XML and practice. The results provide insight into underexplored documents. As described by DeRose, XML linking responds to interconnections between art and document engineering at a perceived limitations of Web document structure, namely by critical moment in the history of the Web, and demonstrate the expanding the functions of hyperlinks beyond one-directional anchors embedded within documents [11]. Both of these Permission to make digital or hard copies of all or part of this work for personal to lists, requires prior specific permission and/or a fee. Request permissions from or classroom use is granted without fee provided that copies are not made or [email protected]. distributed for profit or commercial advantage and that copies bear this notice DocEng ‘18, August 28-31, 2018, Halifax, NS, Canada and the full citation on the first page. Copyrights for components of this work © 2018 Copyright is held by the owner/author(s). Publication rights licensed to owned by others than the author(s) must be honored. Abstracting with credit is ACM. permitted. To copy otherwise, or republish, to post on servers or to redistribute ACM 978-1-4503-5769-2/18/08…$15.00 https://doi.org/10.1145/3209280.3209530 efforts were situated within the existing infrastructure of the <author> tag”), and the Web, but imagined other ways of interacting with documents not afforded by mainstream browsers or existing HTML documentssibling of the and third the childelements of the within �irst them. They respectively standards. tackledlatter described two of the howprimary to problemsde�ine hypertext of networked links hypertextbetween At the height of the “browser wars,” and at a systems: addressing and interlinking. tumultuous moment in the development of HTML standards, The initial development of XLink took place in 1997 Wisniewski‘s work echoed these contemporaneous debates about the role and function of XML for Web documents. In privately examining these two case studies, we aim for deeper historical public drafts published in April and July of that year. Two of the within the W3C's XML Linking Working Group, with understanding of how these systems both critiqued and principal authors of the standard were Steve DeRose and Eve contributed to the variable relationship between Web document structure and metaphor. More than just a technical and the initial XML standardization effort. In 1998, another issue, limitations of hyperlinking like the propensity for linkrot, draftMaler, was both released of whom in which had been XPointer active and in theXLink SGML were community separated or the inability for readers to forge their own links between into separate documents. Additional drafts were released documents, constrained individuals’ abilities to more fully leverage the promised social functions of the Web as a Recommendation in June 20011. The working group also technology to make wide and varied connections across and publishedthrough 1999 a “andrequirements 2000, with” documentthe publication describing of a �inalthe among rich corpora of information. Developing a more nuanced 2 understanding of the complex relationship between document background, design principles, and general use cases of XLink . structure and metaphor can also enrich perspectives and Links in XLink are descriptions of how elements in vocabularies for current efforts to develop Web-based XML documents are interlinked with one another. In HTML document technologies. documents, inserting a link involves inserting one of a few different tags (especially <a> and <form>) within the normal 2 XML Linking and Artists’ Browsers HTML XLink was part of the wave of standardization efforts around href on�low arbitrary of a document, elements, pointing can point to a singleto multiple target targets,using the and can XML (eXtensible Markup Language) in the late 1990s. XML was attribute. With XLink, however, links are able to be de�ined an effort to create a well- appear out of the normal top-to- f documents. Further, links between elements can de�ined subset of SGML (Standard elements appearing in the samebottom document �low oas the links accessible to programmers and application developers, be de�ined without those Generalespecially Markup on the burgeoningLanguage) Worldthat wouldWide Web.be moreThe Web widely had themselves. This means that links can be made even without like HTML could be widely control over the document containing the elements to be and successfully deployed, and XML was meant to pick up that linked. Links between external resources were referred to as shown that a simple subset of SGMLhat was more expressive and "out-of-line links," collections of which were called "linkbases." XLink has enjoyed success in several domain- work, creating a subset of SGML t markup languages derived from XML, including XBRL The W3C began publishing working drafts of the XML speci�ic standardextensible in yet 1996, still andcompatible published with XML SGML as a and Recommen HTML. dation in (eXtensible Business Reporting Language, for describing early 1998. This standard tackled the syntactic features of XML: image format expressed in XML)3, and DocBook (for technical how parsers were meant to understand a string of characters business reports), SVG (Scalable Vector Graphics, a vector as a valid document consisting of tags, attributes, and entities. hyperlinks within and between documents. However, as a The XML standard did not describe anything behavioral or documentation). In all three, XLink was used to de�ine interactive, such as how XML documents should be rendered, generic way to express linking on the Web, XLink had much less transformed, or linked with one another. success. Opera and early versions of Mozilla Firefox both sorts of behaviors were left to other working groups creating developed minimal implementations for “simple”