The Web is vast. Any vast place where human beings gather and use language will house its share of hacks, charlatans, and bloviators. Because source credibility and reliability are crucial persuasive resources, and because it is often difficult or impossible to identify the author of many Web texts, how do audiences decide the crucial question of ethos?
To help answer this important question, Warnick turns to Stephen Toulmin's view of argument that sees argument dynamically, as a social activity. Toulmin wrote The Uses of Argument (1958) as a challenge to the view of reason embodied in the windless enclosures of formal logic, those geometric structures of implications that rarely have much to do with how human beings actually seek to make and justify reasons. Toulmin's jurisprudential approach to argument is, as Warnick puts it, "ordered and reasonable but at the same time situated in fields of practice and knowledge production" (49).
Among Toulmin's contributions was his articulation of a model of argument that applies across knowledge fields yet makes room for the reality that different fields judge arguments and evidence using standards particular to each field. In other words, what is credible within a field is determined by that field’s situated participants.
Using this Toulminian approach, Warnick examines ethos within the field of Web-based political discourse. To do so, she relies on two studies examining how website users judge credibility. The first of these studies suggests that assessments of site credibility proceed in a three-stage process: First, users take in the overall design and layout, often making quick judgments about whether they want to explore the site further. Next, they examine site content (including what, if anything, the site reveals about its authors' identities and qualifications). Finally, they evaulate how site content matches their needs and existing knowledge.
The second of these studies suggests that users assess credibility on the basis of contexts. For example, users expect a site offering travel information to be emotionally engaging and topical while they expect a site offering medical information to give more indicia of source authority. One site is credible if chatty and slick; another is credible if sober and restrained.