Digital library research has demonstrated the impact of content presentation on both search and reading behaviours. In this paper, we scrutinise the influence of ebook presentation on user behaviour, focussing on document thumbnails and the first page view. We demonstrate that flaws in presentation increase the volume of short time-span reading, and reduce the likelihood of long-span reading when compared to other documents. This reflects other patterns of information seeking behaviour that demonstrate increased short-term reading when information content is uncertain, and suggests an ineffective use of reader time on less useful content.