[speek]

For a majority of news articles, the first three sentences is usually more than perfect as a summarization method -- feature stories on the other hand are insane (and that's why we have things like Lexical Chains: http://acl.ldc.upenn.edu/W/W97/W97-0703.pdf)

[MojoJolo]

We use lexical chains in our undergraduate thesis. Not a fan of it. AFAIK, not much of the text we summarized are affected by our lexical chain feature. It is a minor feature in our thesis. We combined lexical chains with other summarization techniques.

It's a good concept, but chains maybe a long one and may not be serve its "summary" purpose (maybe that's only for our case). In our thesis, we just extract the 5 most important sentences. Sentences with a lexical chain to a sentence or sentences may consume all the 5 sentences we needed and not leaving a room for other sentences in the text.