i think that'd be quite easy, being honest)
i've been working on the same concept to that app, it's hackable in 3-5 weeks :) especially having some great tools such as Weka or Mahout
again, one person may be satisfied with a certain achieved result, but that may work not quite well for other person. just for instance, clusterization or topic extraction. you should have some knowledge about what you want to get, what are the possible outcomes of investigation, and dig into data to get what you need. generic approach will give broad resultset that may require some additional effort for real-world usage.