"How rare is it to find a new problem domain these days? Most if not all problems tackled with deep learning have already been done in one form or the other."

Curious if anyone's done this: deep learning on DOM trees, to recognize portions of HTML pages. This has elements in common with both CNNs (where you want surrounding context - parents, ancestors, siblings, and descendants - to influence the recognition of a particular DOM element) and with RNNs (because elements may have an unbounded number of children, and potentially a recurring substructure), but I don't know offhand how you would combine them to solve the problem.

Anyone working on this? A quick literature search turned up nothing.