Ask HN: How to automatically monitor keywords (eg. Java, DBA...) on job sites?

If I look through IT/programming jobs posted on a service such as s1jobs.com, I'll start to notice patterns like lots of companies looking for J2EE programmers, not so many looking for Haskell programmers, and so on. I want to quantify these patterns. How could I implement some sort of script to crawl part of the site daily, count the occurrences of repeated words (obvious shortcut would be to discard any word not beginning with a capital letter, and then any other words that are non-helpful like simply 'The' or 'A' or 'Candidates'), so that I can see what skills are most in demand?