I actually tried Calais. Here are my results. (Score 1)

I didn't try 5000 documents, but only two, one general text and one financial news. The results I got results were promising, but at the same time IMO not reliable and actionable enough that I would use this technology today to buy/sell stocks automatically. - http://lebleu.org/blog/2008/02/10/kicking-the-tires-with-opencalais/ - http://lebleu.org/blog/2008/02/03/microsoft-offer-to-buy-yahoo-semantic-analysis-by-opencalais/