This paper reports on the findings of a study that compared models of online source analysis. It is argued that there is disconnect between print-based (classical) approaches to teaching online source analysis in history, and how students are informally analysing online information. It will be argued that this disconnect makes it difficult for students to effectively analyse online sources containing false and misleading information. In order to address this issue, formal web-based approaches to online source analysis need to be developed and evaluated. The paper puts forward Shane Borrowman's (1999) application of the Aristotle's concept of Ethos as a framework through which online source analysis can be formalised, and student critical awareness can be activated. The study was conducted with Australian senior high school students, who evaluated Holocaust denial websites before and after an intervention. The responses in each case were compared, and it was found that formalising students’ web-based models of analysis significantly increased the depth and criticality of their engagement. This paper contributes to the debate on how to most effectively activate student critical awareness when analysing online historical sources.