MongoDB has introduced a new Hash-based Sharding Feature in version 2.4, which allows users to easily set up randomized shard keys and automatically distribute data across shards for isolated document writes and reads. This feature is particularly useful for workloads with lots of individual document writes or reads, such as key/value lookups. The new feature provides better distribution of chunks on shards, making it easier to manage sharded collections. However, users should be aware that ranged queries and multi-updates must hit all shards, and the feature can only distribute documents based on a single field. Additionally, tag-aware sharding is compatible with Hash-based shard keys, allowing users to pin collection data to specific shards or ranges of shards.