I wrote a post about building a recommender using Mahout on Amazon EMR and it finally went live: http://blogs.aws.amazon.com/bigdata/post/Tx1TDK3HHBD4EZL/Building-a-Recommender-with-Apache-Mahout-on-Amazon-Elastic-MapReduce-EMR
Please feel free to share the link to get the word out. Best Andrew
