We have worked through some key concepts in trying to define Digital Humanities. An important distinction about DH which Matt pointed out is the emphasis on the methodology of building, which is by nature collaborative work. Another very exigent issue is this–in what ways is DH in part a reaction against the corporatization of the academy, and in what ways is it possible that the growth of DH may actually further the erosion of traditional academics (i.e. tenured professors teaching in actual classrooms)? I don’t have an answer to that, but it is something to watch.
It seems to me that there has been a pent-up demand for something like DH which will incorporate new tools and technologies, new methods of community-building, new ways of peer-review and publishing, and that the time is ripe for something to jell, to pull a lot of diverse people together under a “big tent”. It’s an exciting thing to see a new field forming, and even more exciting to jump into that field.