Two practical applications from top of my head: * Do you want to build an index (for big data?), so that you can access your data fast (thing about a database)

Two practical applications from top of my head: * Do you want to build an index (for big data?), so that you can access your data fast (thing about a database). Well, the index construction is likely to do some sorting internally. * MapReduce algorithm has indeed more phases... one of it is sorting...so yes, when you are porocessing big data with map reduce, then the data is being sorted at some point.