Carlos Castillo did a fine job of presenting "An Optimization Framework for Query Recommendation" by Anagnostopoulos, Becchetti, Castillo and Gionis. My favorite part was using Cavafy and Machiavelli as presentation vehicles for two different utility functions they evaluated: the former aggregating utility along every step of a multi-step process, the latter ignoring the journey and solely caring about the value derived in the very last step. These utility functions were presented in the context of query reformulation, the query suggestions search engines provide users with to aid them in finding what they are looking for. I am not quite sure how they came up with this great metaphor but it may just be that the authors are Greek and Italian.
The second presentation I enjoyed was given by Alan Mislove. I think he nailed it by selecting just right level of abstraction for his talk. Not too much detail, but enough to maintain my interest and entice me to read their paper: "You Are Who You Know: Inferring User Profiles in Online Social Networks". The main idea here is that information that you may consider private and are unwilling to publish can potentially be inferred by information your friends reveal; not necessarily directly about you, but about themselves. Because of the homophily present in social networks what your friends say, can be telling about you. Hompophily was definitely word of the day today; it was featured in three different presentations. All in all I think this paper underlined some concerns anyone with an online presence should be having.
My only gripe so far has been the heat in the auditorium - I think, by the end of the day, it makes everyone feel more tired than they already are. But other than that WSDM has been very enjoyable so far.
PS: The Twitter feed disappeared during Thursday afternoon's sessions but was back this morning. I guess people must be enjoying it!