I came across Joshua Sternfeld's definition of 'digital historiography' while I was writing my thesis, and two parts of it very neatly described what I was up to – firstly, the 'interdisciplinary study of the interaction of digital technology with historical practice' – and secondly, seeking to understand the 'construction, use, and evaluation of digital historical representations'. However, the size and shape of the gap between digital historiography and 'digital history' is where I tend to get stuck. I've got a draft post on the various types of 'digital history' that's never quite ready to go live.* Is digital history like art history – a field with its own theoretical concerns and objects of study – or will it eventually merge into 'history' as everyone starts integrating digital methods/tools and digitised sources into their work, in the same way that social or economic history have influenced other fields?
Anyway. While I may one day write that post, Melissa Dinsman's interview with Laura Mandell, The Digital in the Humanities: An Interview with Laura Mandell, puts two vital questions that help focus my enquiry:
The real reason for me for talking about the digital humanities is that we need to realize the humanities never were the humanities. They are the print humanities and they are conditioned by print. So the question the term “digital humanities” poses is: How must humanities disciplines change if we are no longer working in a print world? This question, to me, is crucial. It is an intellectual question. And the question being proposed is: What happens to the humanities when digital methodologies are applied to them or when they start to interrogate digital methodologies? Both of these questions are crucial and that is what this term — “digital humanities” — keeps front and center.
The whole series of 'The Digital in the Humanities' interviews Dinsman has conducted provide a thoughtful insight into the state of the field.
* Partly because 'digital history' changes at a fairly constant rate and my thoughts shift correspondingly.
 Joshua Sternfeld, ‘Archival Theory and Digital Historiography: Selection, Search, and Metadata as Archival Processes for Assessing Historical Contextualization’, American Archivist 74, no. 2 (2011): 544–75, http://archivists.metapress.com/index/644851P6GMG432H0.pdf.