Summarizing

I've gotten the MEAD summarizer working on some hand-clustered groups of documents, but it's difficult to know how well it's actually doing on this data, and how well it will scale when we apply it to larger clusters. However, this gives us some ideas as to which sentence ranking and reranking methods we ought to try. Maybe it'll also be a good idea to try slicing up posts into paragraphs, and considering all of them as separate documents, since that could give us more flexibility to deal with posts which cover many topics.