When you do a production search you are returning points on a map (or table) that represent wells that match the search criteria.
For production, which is often reported by lease, you might notice numerous wells on a lease that show the exact same monthly production and cumulative figures. This is because each well on a lease will show the production for the entire lease.
By selecting the Aggregation option you can choose to display one randomly selected well to be representative of the entire lease's production.
This option forces the search to return one well for each lease which can help you get around the truncation limits for large searches.
See Market View Search for more information.