If one considers the idea of map reduce to be taking a set of data and ending up with a subset that is relevant, I've used tons of simple things to do that, and

If one considers the idea of map reduce to be taking a set of data and ending up with a subset that is relevant, I've used tons of simple things to do that, and never Hadoop. I think parsing logs to find pain areas or potential exploit/exfil is a map reduce job, for instance, and grep or awk can manage that just fine.