Apache Hive is a data warehouse system built on top of Hadoop. Using SQL-like language you can query data stored in the Hadoop filesystem (HDFS). Those queries are then translated into Map Reduce jobs and executed on your cluster.
As an example we’ll analyze tweets from the Twitter Streaming logs and calculate the top 5 hashtags per day which are associated with positive sentiment signals (smileys).
You can imagine how this can be expand this to simple sentiment analysis on your (potential) customer feedback.