I made a javascript based automated scraper in a win7/vista desktop gadget. It was originally for dislplaying the remaining credit on my mobile. You put in search terms and a website and it scrapes it and tries to return what it thinks you are looking for (weather, stock prices, remaining blance etc). It works ok. I think there is definetly demand for a well made scraper/alert app/service though.
App is here http://robotification.com/creditile/
Also didn't yahoo make a thing for scraping this 'Yahoo Pipes' or something.