(Not sure if quoting you is the right way to go about this but - )
I guess that's my problem here, my one experience with DH was digitizing and marking up manuscripts so they could go online. (So much of medieval French hagiography has not been transcribed or even catalogued.) I suppose, broadly, it's the intersection of technology and history. Using software for data visualization, mapping, archival stuff.
It's hard to say what I mean since it seems like there really is no standard curriculum yet and the coursework varies from school to school, if it's even offered at all.