Google itself is using Hadoop in its University program, see http://code.google.com/edu/parallel/mapreduce-tutorial.html, and encouraging universities such as Berkeley to expose students to MR in their CS curriculum.
It even has a biblio entry of 'Open Source MapReduce: http://lucene.apache.org/hadoop/'. Given the hard time Google has recruiting people with skills that match their infrastructure, sueing around Hadoop would be a very unclever move as no one would then be able to train him/herself on those types of technologies. Let's face it, infrastructure and use of technologies such as MR give Google a headstart, not MR per se. Just my 2ct worth. Mathias.
