Picking a random item from a collection is used in many cases. For example, you want a random item from the collection photos. Currently this can be accomplished by counting the resulting query, computing a random index within that count, and then getting that item with that random index.
A easier approach would be requesting a random item directly from mongo given a query
// this would act like .next() but instead would simply return a random item that matches the query
// this would act just like find_one, except it would return a random item that matches the query