By the way, regarding your other points (although I think they are a bit off topic): As for the cost of corpora: That number is extremely variable, and in many

By the way, regarding your other points (although I think they are a bit off topic): As for the cost of corpora: That number is extremely variable, and in many cases (outside of newswire, in particular) you might have your own training data. And then there is non-english NLP, too. Last but not least, tagging text is not the only thing you can apply a CRF (or any graphical model) to... Regarding paying for a Stanford (or any other software) license: That is precisely what the text linked to explains - that you do not need to pay for such stuff - not only are there free tools around, some of them are far better than the commercially restricted ones.