Zaratustra

Hello, I have a small problem but I need quick help. For a few weeks I'm reading about Machine Learning issues, and in particular ML methods used in Information Retrieval problems. I try to find application ML in IR which is especially important in the last 3-5 years (not 10-12 years), and it is possible to perform a very simple test in WEKA, KNIME or Mloss programs. What kind of applications would be easy to implement in these programs for the ML beginner ? What do you think?