The meeting got all semantics-y and I think I have been clear in the past about my feelings about semantics, so I won't expand on that here except to say that on the one side, if semantics are to be applied to data or papers or web pages by their authors, the tags are being applied with strong biases and incentives (all meta-data are wrong). On the other side, if semantics are to be generated by machines, then the tags are all probabilistic and we should not call them semantics but rather hyper-parameters and provide probability distribution functions over them, prior and posterior.
Highlights of the day included Alex Gray's talk on fast methods, which was followed by a short but useful discussion of discriminative and generative methods and the relationship to noise models and utility. Also Ashish Mahabel gave a nice overview of his classifiers for CRTS, which includes exactly the elements needed to do utility-based decision-making and experimental design. Between talks, Bob Hanisch and I discussed getting Astrometry.net data into the Virtual Observatory. I think that would be good for both projects. (And I guess, in some sense, it means that I will be publishing semantics. Oh well!)