A similar thing is going on with "Data Journalism" which is, again, viewed cynically, a way to keep one's job but take advantage of incorporating sheer masses of information and "infographics" into conventional stories.
Asking "what is Digital Humanities" also reminds me of the angst certain communities felt over "what is blogging" and "what does it mean to be a blogger." I sat through many conference sessions on such topics. I did not gain much insight.
I worry that anything digital is ephemeral, and that is not a good thing for the humanities. I prefer dusty old books. They're a proven technology that tend to stick around long after whatever the latest file format, O/S, or cloud solution has passed from being in favor to being forgotten.
Finally, I will say that if the field of Digital Humanities helps imbue in people a better sense of, and better set of skills for, information comprehension, information composition, and critical thinking in the digital age of always-on, ubiquitous firehoses of noisy information about the world and everyone in it, then that is a good thing. We desperately need upcoming generations to be really good at what I call the three C's (composition, comprehension, and critical thinking). Just a brief glimpse at Twitter or any cable news outlet would suggest these skills are not often on display anymore.