There are lots of open source tools for these niches.

For sentiment analysis, I'd recommend: http://nlp.stanford.edu/sentiment/code.html

For web scraping, a popular option is Scrapy: http://scrapy.org/

And an unknown web scraping option (and shameless plug): https://github.com/MachinePublishers/ScreenSlicer

For browser automation see Phantom JS or Selenium: http://phantomjs.org/ http://docs.seleniumhq.org/

For an open source IFTTT-inspired project: https://github.com/cantino/huginn/